TCA-丙酮沉淀法浓缩蛋白
真菌蛋白提取方法
真菌蛋白提取方法一TCA/丙酮法1 液氮将菌体研磨为粉末;2 向匀浆中加入10倍体积的丙酮(含13.3% (w/v) TCA和0.093% β巯基乙醇),过夜沉降;3 4 度20,000g 离心15 min;4 移处上清,用冰冷的含0.07% (v/v) β-巯基乙醇的丙酮清洗沉淀两次;5 离心后,沉淀干燥至丙酮挥发完全。
二酚抽提法1 在液氮中将 1g 菌体研磨为粉末2 加入 6 ml 水饱和酚(buffer-saturated phenol)和 2 ml提取液(20mMTris-Cl, pH 7.5, 0.5% Triton X-100 (v/v), 0.5M EDTA, pH 7.5, pH 8.0,0.07% β-巯基乙醇, protease inhibitors)。
3 在4度混合30分钟。
4 12000 rmp 离心1min,使两相分开。
5 弃沉淀,吸取上层的苯酚相,加入5倍体积的冷丙酮,-20度沉降2h。
6 12000 rmp,4度,离心15分钟沉淀蛋白,弃去上清。
7 沉淀干燥至丙酮挥发完全。
三提取液抽提丙酮沉淀法1 预先将研钵置于-20℃的冰箱内冷冻。
2 取液氮冻存的菌体,放入预冷的研钵内研磨至粉末状。
3 向匀浆中加入2倍体积的抽提液(20mM Tris-Cl, pH 7.5, 0.5% Triton X-100(v/v), 0.5M EDTA, pH 7.5, pH 8.0, 0.07% β-巯基乙醇, protease inhibitors)。
4 混匀后4度震荡30分钟,以便蛋白溶解。
5 12000 rmp,4度,离心15分钟,吸取上清于另一EP管中。
7 向上清液中加入5倍体积的预冷丙酮(含有0.07%β-巯基乙醇),混匀,-20℃,2小时沉淀蛋白质。
8 12000 rmp,4度,离心15分钟沉淀蛋白。
弃去上清,沉淀用乙醇洗三次,自然干燥蛋白沉淀。
四甲醇氯仿水沉淀法Chloroform /Methanol/Water Precipitation1 预先将研钵置于-20℃的冰箱内冷冻。
TCA蛋白沉淀方法
100% (w/v)三氯乙酸的配制方法:500g三熬乙酸用227ml水来溶無,所得溶液即100%三氯乙酸溶液。
避光,4度保(preparation of 100% TCA: 454ml H2O/kgTCA. Maintain in dark bold cat 4oC.Bc careful, use gloves!!!).培养基上清直接电泳跑出来的条带经常很难看,可以TCA沉淀浓缩后跑电泳,一般表达量大于可以看到明显条带,这是我用的TCA沉淀方法,效果很好:1 •菌液1000(也,离心5分钟,收集表达上清。
2•取500-10(X)ul ±清于EP管中,加入1/9体积的100%TCA,颠倒1()次混匀。
3•样品置于冰浴中大于0.5小时,过夜效果更好。
4.15000g,离心10-20分钟,可见有棕黑色沉淀,倒掉上清,将EP管倒扣在吸水纸上轻轻控几下,除去残余在管口的液体。
5.将EP管倒置于吸水纸长,37度烘箱10-20分钟,待管底无明显液体残留,如杲管壁还残留有液体,可以吸水纸吸掉。
可以改成室温或用电吹风,关犍是除去管底和管壁残余液体。
6.15OOOg,离心10-20分钟,用20ul枪头尽量吸去管底残余的液体,此步骤要快,不然沉淀容易散开,降低蛋白回收率,一般最多几ul或者没有,注意不要吸到沉淀。
7.EP管倒置于吸水纸长,37度烘箱5分钟,确认管壁和管底没有液体残留。
&加入20-50ul Loading buffer, 95度加热lOnim, —般沉淀会自动溶解,如果不溶,用手指轻弹管壁或用2()ul枪头轻轻吸打,注意整个操作尽量不要碰到管壁, 因为管壁可能沾有残余TCA。
如果蓝色的Loading buffer不变成黄色,说明残余TCA吸弃了干净,如果变黄,一般不影响电泳。
此方法连丙酮洗这一步都省了,而且不影响电泳效杲。
或者第5步和第6步改为丙酮洗:5•加入2()0u】冰冷的丙酮,用手指轻弹EP管,洗去管底和管壁残余的TCA。
植物组织蛋白提取方法
植物蛋白质提取方法总汇一、植物组织蛋白质提取方法1、根据样品重量(1g 样品加入3.5ml 提取液,可根据材料不同适当加入),准备提取液放在冰上。
2、把样品放在研钵中用液氮研磨,研磨后加入提取液中在冰上静置(3-4 小时)。
3、用离心机离心8000rpm40min4 C或11100rpm20min4 °C4、提取上清液,样品制备完成。
蛋白质提取液:300ml1 、1Mtris-HCl (PH8)45ml2、甘油(Glycerol )75ml3、聚乙烯吡咯烷酮(Polyvinylpolypyrrordone )6g这种方法针对SDS-PAGE垂直板电泳!二、植物组织蛋白质提取方法氯醋酸—丙酮沉淀法1 、在液氮中研磨叶片2、加入样品体积3倍的提取液在-20 C的条件下过夜,然后离心(4 C 8000rpm以上1 小时)弃上清。
3、加入等体积的冰浴丙酮(含0.07%的3 -巯基乙醇),摇匀后离心(4C 8000rpm 以上1 小时),然后真空干燥沉淀,备用。
4、上样前加入裂解液,室温放置30 分钟,使蛋白充分溶于裂解液中,然后离心(15C 8000rpm以上1小时或更长时间以没有沉淀为标准),可临时保存在 4 C待用。
5、用Brandford法定量蛋白,然后可分装放入-80 C备用。
药品:提取液:含10%TCA和0.07%的3 -巯基乙醇的丙酮。
裂解液:2.7g尿素0.2gCHAPS 溶于3ml灭菌的去离子水中(终体积为5ml),使用前再加入1M的DTT65ul/ml。
这种方法针对双向电泳,杂质少,离子浓度小的特点!当然单向电泳也同样适用,只是电泳的条带会减少!三、组织:肠黏膜目的:WESTERN BLO检测凋亡相关蛋白的表达应用TRIPURE提取蛋白质步骤:含蛋白质上清液中加入异丙醇:(1.5ml每ImITRIPURE用量)倒转混匀,置室温10min离心:12000 g,10min,4 度,弃上清加入0.3M盐酸胍/95 %乙醇:(2ml每ImITRIPURE用量)振荡,置室温20min离心:7500g ,5 min ,4 度,弃上清重复0.3M 盐酸胍/95 %乙醇步2 次沉淀中加入100%乙醇2ml充分振荡混匀,置室温20 min离心:7500g ,5min,4 度,弃上清吹干沉淀1 % SDS溶解沉淀离心:10000g,10min ,4 度取上清-20 度保存(或可直接用于WESTERN BLO)T存在的问题:加入1%SDS后沉淀不溶解,还是很大的一块,4度离心后又多了白色沉定,SDS结晶?测浓度,含量才1mg/ml左右。
TCA-丙酮沉淀法蛋白提取
TCA-丙酮沉淀法蛋白提取仪器:Eppendorf 冷冻离心机(Eppendorf)、组织匀浆器、超声破碎仪主要溶液配置:1.10mL SDS裂解液1%DTT,2% SDS,10%甘油,50mM Tris-Hcl(pH6.8)。
配置:称取0.1g DTT,0.2g SDS,加入1mL甘油和1mL的0.5MTris-Hcl(pH6.8),然后定容至10mL。
2.10mL Triton样品溶解液浓度:150mM NaCl,1%Triton-X-100,50mM Tris-HCl(pH8.0)配置:称取0.087gNaCl、加入0.1mL Triton-X-100、500μL 浓度为1M的Tris-HCl (pH8.0) 加入约9.4mL水,混合溶解均匀。
保存:4度保存。
3.1mL尿素样品溶解液(现配现用)浓度:9M 尿素,4%CHAPS,1% IPGBuffer,1% DTT,配置:称取0.54g尿素、加入0.04g CHAPS、再加入0.56mL双蒸水,溶解后分装-20度冷冻保存,使用前融解后按0.98mL加入0.01g DTT(DTT过早加入会失效)和10μL Buffer的比例混合溶解均匀,最后再加入痕量溴酚蓝。
保存:-20度保存。
4.RIPA裂解液:浓度:50 mmol/L Tris-HCl (pH 8.0),150 mmol/L NaCl,0.2 g/L叠氮钠,1 g/LSDS 100 mg/L Aprotin,10 g/L NP-40,5 g/L去氧胆酸钠,100 mg/LPMSF。
(RIPA裂解液有强、中和弱三种类型,其试配置略有差异)配置:称取:0.07882g Tris-HCl,0.08775g NaCl,0.002g叠氮钠,0.01gSDS,0.001g Aprotin,0.1g NP-40,0.05g去氧胆酸钠,0.001g PMSF。
注:以上列举了一些常见的裂解液,除此之外还有多种类型的裂解液,需要研究者根据自己研究的材料和实验目的选择合适的裂解液提取蛋白。
烟草叶片蛋白3种提取方法的比较研究
烟草叶片蛋白3种提取方法的比较研究摘要:使用酚/SDS法、Tris-HCl法及TCA/丙酮沉淀法提取烟草(Nicotiana tabacum)叶片蛋白,从终产物形式、颜色、提取时间、蛋白产量、SDS-PAGE电泳图谱等方面对3种方法进行比较,对提取的烟草叶片蛋白进行Western Blotting检测来评价3种方法提取蛋白的效果。结果表明,与2种常用方法相比,酚/SDS法具有快速、操作方便等特点,提取的蛋白纯度高、种类丰富,可用于Western Blotting检测,是一种合适的提取植物组织中蛋白的方法。关键词:烟草(Nicotiana tabacum)叶片;蛋白;Tris-HCl法;TCA/丙酮沉淀法;酚/SDS法Comparison Study on Three Methods for Tobacco Leaf Protein Extraction Abstract: Protein was extracted from tobacco(Nicotiana tabacum) leaves by three methods, phenol/SDS method, Tris-HCl method and TCA/acetone precipitation method. The extracting efficiency of the three methods was evaluated through the color and form of product, extraction time, protein yield and SDS-PAGE. Furthermore, the extracted protein was detected by Western Blotting. The results showed that compared with the other two methods, phenol/SDS method was faster and more convenient, and the protein extracted was with high quality, rich in protein species, and suitable for Western Blotting, thus was an appropriate method for extracting protein from plant tissue.Key words: tobacco(Nicotiana tabacum) leaf; protein; Tris-HCl extraction method; TCA/acetone precipitation; phenol/SDS extraction method蛋白质组学(Proteomics)是随着基因组学发展而发展起来的、在整体水平上研究细胞内蛋白质的组成及其活动规律的学科。由于其能够阐明基因表达产物——蛋白在生物体内的相对含量、修饰化信息,蛋白质与其他生物大分子的相互作用等诸多内容而日益成为现代生物学的研究热点。在蛋白质组研究中,蛋白样品制备是分析的起始和基础,蛋白提取质量和效果对后续的研究分析有重要影响[1,2]。植物组织含有较厚的细胞壁,给组织中蛋白质的提取增加了一定的难度。目前常用的植物蛋白的提取方法有两种,一种是普通Tris-HCl提取法,该方法通过选择适当的提取缓冲液pH,将植物中的可溶性蛋白尽可能地溶解;另一种是TCA/丙酮沉淀法,该方法中TCA作为蛋白质变性剂,能有效抑制丝氨酸蛋白酶和巯基蛋白酶的活性,减少蛋白损失,因此得到较为广泛的使用[3-6]。但以上两种方法都不能有效地去除产物中的非蛋白物质,会对后续的研究产生不利的影响。而酚/SDS蛋白提取法中,利用酚在SDS这种阴离子型表面活性剂的存在条件下能充分溶解蛋白的特点,可以取得在较短的时间内充分溶解植物组织中蛋白的效果,得到的蛋白纯度更高[7,8]。目前该方法在国内使用得较少,特别是在烟草样品中尚未见报道。本研究同时使用酚/SDS法、Tris-HCl法及TCA/丙酮沉淀法3种方法从烟草叶片中提取蛋白质,从终产物形式、颜色、提取时间、蛋白产量、SDS-PAGE电泳结果等方面进行比较,并使用糖基转移酶抗体对提取的烟草叶片蛋白进行免疫学检测,以评价3种方法提取蛋白的效果,为植物蛋白的提取和蛋白组学研究提供参考。1 材料与方法1.1 材料和试剂烟草叶片(W38)来自中南民族大学生命科学学院国家民委生物技术重点实验室。主要试剂:NC膜购自Whatman公司;ECL Western Blot System购自碧云天公司;Tris、三氯乙酸等化学试剂为国产分析纯;糖基转移酶多克隆抗体由北京华大蛋白技术有限公司制备。1.2 蛋白提取方法1.2.1 Tris-HCl提取法准确称取0.5 g叶片,剪碎后加入0.25 mL Tris-HCl溶液冰浴研磨,再加入0.75 mL提取液(7 mol/L尿素、2 mol/L硫脲、0.4% CHAPS、10 mmol/L DTT),研磨至匀浆后,转移至1.5 mL离心管中,10 000 r/min离心10 min,上清液为所需的总蛋白。1.2.2 TCA/丙酮沉淀法取0.5 g叶片,用液氮研磨充分,加入5 mL预冷的TCA 提取液(含质量分数10%的TCA、20 mmol/L DTT、1 mmol/L PMSF的丙酮溶液)充分混合后,-20 ℃放置1 h;13 000 r/min、4 ℃离心15 min,取沉淀;再加入5 mL预冷的样品洗涤液(20 mmol/L DTT、1 mmol/L PMSF的丙酮溶液),充分混合后,-20 ℃放置1 h;13 000 r/min、4 ℃离心15 min,取沉淀;用密封膜封口,用针在膜上扎几个小洞,低温冷冻干燥。置于-80 ℃保存或直接进行蛋白电泳。1.2.3 酚/SDS蛋白提取法取0.5 g烟草样品,液氮中研磨至粉末,快速转移至7 mL试管,加入5 mL预冷的质量分数为10%的TCA丙酮溶液,振荡混合均匀后,12 000 r/min、4 ℃离心3 min,弃上清;加入5 mL含有0.1 mol/L乙酸铵的体积分数为80%的乙醇溶液,振荡混合后12 000 r/min、4 ℃离心3 min,弃上清;再加入5 mL体积分数80%的丙酮,涡旋振荡直至沉淀充分分散,12 000 r/min、4 ℃离心3 min,弃上清,室温干燥10 min以除去剩余的丙酮,加入2.5 mL苯酚/SDS溶液,振荡混匀后,放置5 min,12 000 r/min、4 ℃离心3 min;转移上层苯酚相(约1~2 mL)至新的7 mL 管中,加入含有0.1 mol/L乙酸铵的乙醇溶液,置-20 ℃中10 min或过夜,12 000 r/min、4 ℃离心5 min,小心弃上清。用无水乙醇洗沉淀,再用体积分数80%的丙酮洗沉淀。最后让蛋白自然干燥,或根据实验需要用缓冲液溶解蛋白,保存在-80 ℃冰箱,或直接进行蛋白电泳。1.3 检测方法考马斯亮兰G-250法测蛋白含量[9];SDS-PAGE电泳检测,按照文献[10,11]所述方法进行;Western Blotting检测:取发育状况接近的烟草叶片,分别用3种方法提取总蛋白,进行SDS-PAGE电泳,然后通过蛋白转膜、丽春红染色检测、封闭、标记一抗、洗脱一抗、标记二抗和杂交、再洗脱、化学发光法显色检测结果等步骤进行分析[12,13]。2 结果与分析2.1 3种方法提取的蛋白质质量和产量比较对3种提取方法得到的烟草叶片蛋白形式、颜色、提取时间及蛋白产量进行比较(表1),可以看出,Tris-HCl提取法所得产物为绿色,这是由色素等杂质成分未能被完全去除而导致。该方法虽提取速度快、产量高,但蛋白质量不高,所含杂质较多。TCA/丙酮沉淀法用液氮充分研磨烟草叶片,同时加入蛋白酶抑制剂PMSF,降低了蛋白降解损失,故蛋白产量最高。但是多次洗脱后样品颜色仍为淡黄色,这可能是因为烟草叶片中的一些物质能与蛋白共沉淀,导致终产物含有杂质。此外,此方法操作耗时较长,会导致蛋白样品的损失和降解。使用酚/SDS法提取蛋白,酚能够有效溶解蛋白,并在SDS存在下,其溶解效果更好,可溶解的蛋白更多,且该方法能有效去除非蛋白物质,非蛋白类成分较其他两种方法都少,获得的产物为白色。虽然该方法的蛋白产量较TCA/丙酮沉淀法低,提取所需时间长于Tris-HCl法,但蛋白较纯。2.2 SDS-PAGE检测结果使用常规的SDS-PAGE对3种方法获得的烟草蛋白样品进行比较分析,在蛋白上样量为20 μg时,Tris-HCl法提取的蛋白中检测到10个条带,TCA/丙酮沉淀法提取的蛋白电泳检测出14条条带,酚/SDS法提取的蛋白有12条条带(图1)。Tris-HCl 法提取的蛋白条带较少,说明只提取到了部分蛋白,可能是该方法采用冰浴研磨,细胞破碎不够充分,只能得到植物组织中的部分可溶性蛋白。当蛋白上样量为40 μg时,酚/SDS法所得的蛋白条带最多(图2),说明该方法提取的蛋白种类最多,提取效果比较好。2.3 Western Blotting检测结果使用Western Blotting,以烟草糖基转移酶抗体为探针检测3种方法获得的蛋白,结果显示普通Tris-HCl法和TCA/丙酮法提取的蛋白均未出现任何杂交信号,只有酚/SDS法提取的蛋白出现杂交信号(图3),这表明酚/SDS法提取的蛋白用于Western Blotting分析能得到较好的效果。3 结论3.1 蛋白提取质量在蛋白提取中,杂质的去除是一个主要问题[2],本研究中酚/SDS法提取的蛋白颜色最浅,所含杂质少,有利于后续的蛋白质组分析。另外,该方法步骤简单,提取时间较短,能在4~5 h内完成,具有操作方便、快速的特点。其他两种方法提取的蛋白质均含有较多杂质,不利于后续实验的进行。3.2 电泳和Western Blotting检测对3种方法提取的蛋白进行电泳检测,Tris-HCl法只提取到了部分蛋白。TCA/丙酮沉淀法所得蛋白条带虽多,但是该方法需要的时间长,容易产生蛋白样品的降解,从而导致蛋白电泳结果不稳定。而酚/SDS蛋白提取法所得条带较多,重复性好,能够得到良好的一维电泳图谱。此外,本研究使用Western Blotting对烟草叶片蛋白中的糖基转移酶进行了检测。结果显示酚/SDS法提取的烟草叶片蛋白表现良好,可用于后续分析。酚/SDS法提取植物蛋白,可获得高质量和较高产量的目标产物,为有效提取植物叶片蛋白提供了有力的依据,也为后续的蛋白分析实验打下了良好的基础。参考文献:[1] WANG W, VIGNANI R, SCALI M, et al. A universal and rapid protocol for protein extraction from recalcitrant plant tissues for proteomic analysis[J]. Electrophoresis,2006,27(13):2782-2786.[2] 兰彦,钱小红.蛋白质组分析中蛋白质分步提取方法的建立[J]. 生物化学与生物物理进展,2001,28(3):415-418.[3] 曾亚. 水稻抗病基因介导的抗病反应中蛋白质表达谱的比较分析[D]. 武汉:华中农业大学,2008.[4] 严顺平. 水稻响应盐胁迫和低温胁迫的蛋白质组研究[D]. 北京:中国科学院研究生院,2005.[5] 赵敏. 水稻两优培九不同氮素处理叶片和籽粒蛋白质组学研究[D]. 福州:福建农林大学,2008.[6] 汪家政,范明.蛋白质技术手册[M]. 北京:科学出版社,2000. [7] WANG W, SCALI M, VIGNANI R, et al. Protein extraction for two-dimensional electrophoresis from olive leaf, a plant tissue containing high levels of interfering compounds[J]. Electrophoresis,2003,24(14):2369-2375.[8] FAUROBERT M, PELPOIR E, CHA B J. Phenol extraction of proteins for proteomic studies of recalcitrant plant tissues[J]. Methods in Molecular Biology,2006,355:9-14.[9] LI F F,WANG Y Y,LIU G F, et al. Cloning and expression of wheat heat-shockprotein 60(HSP60) gere in E. coli[D]. Agricultural Science & Technology,2010,11(1):5-7.[10] 郭尧君. 蛋白质电泳实验技术[M]. 北京:科学出版社,2005.[11] 丁.萨姆布鲁克, D.W.拉塞尔. 分子克隆实验指南[M]. 第三版.黄培堂,王嘉玺,朱厚础,等译.北京:科学出版社,2002.[12] 王卓. 一个新的烟草糖基转移酶的过表达及相关研究[D]. 武汉:中南民族大学,2008.[13] 王雪,谭艳平,周杰,等. 一个烟草糖基转移酶启动子在转基因烟草植株中的表达分析[J]. 安徽农业科学,2010,38(18):9426-9428.。
植物蛋白质提取方法
一、植物蛋白质提取1. TCA-丙酮法(1)称量一定量的样品置于液氮预冷的研钵中,加少许PVPP,反复加液氮研磨至粉末。
(2)研磨好的样品用10 倍体积(w/V)的10%的TCA-丙酮溶液悬浮,加入0.1 M PMSF、1 M DTT 至终浓度为1 mM PMSF、10mM DTT,超声5 分钟,于-20℃静置6 小时或过夜后,4℃,20000g 离心15 分钟,弃上清。
(3)沉淀用10 倍体积于样品的丙酮溶液重悬浮,于-20℃静置1 小时后,4℃,20000g 离心15 分钟,弃上清。
(4)重复步骤(3)一次。
(5)沉淀用10 倍体积于样品的乙醇/乙醚=1:1 洗,于-20℃静置1 小时后,4℃,20000g 离心15 分钟,弃上清。
(6)重复步骤(3)一次。
(7)取出沉淀真空干燥约5 分钟,除尽有机溶剂。
(8)按10mg 干粉末加200 微升裂解液的比例,加入1 mM PMSF、10mM DTT,超声5分钟,充分溶解1 小时,10℃,35000g 离心30 分钟,上清为所需的蛋白溶液。
(9)用Bradford 法测定蛋白样品的蛋白浓度。
(10)蛋白样品溶液小量分装,-80℃保存。
注意事项:(1)TCA 有利于去除酚类色素等物质,但不利于蛋白的抽提,使用浓度不宜过高,在后面丙酮处理中,尽量除去。
(2)蛋白样品保存:样品浓度不宜过高,建议将高浓度样品适度调整,为避免反复冻融应分装保存,长期保存用-80℃,短期保存用-20℃。
(3)1M DTT:0.1542g DTT 用1ml MilliQ 水溶解,-20℃保存。
(4)0.1M PMSF:0.0174g PMSF 用1ml 异丙醇溶解,-20℃保存。
沉淀蛋白质的常用方法
沉淀蛋白质的常用方法(TCA、乙醇、丙酮沉淀蛋白操作步骤)2010-08-18 15:19TCA-DOCFor precipitation of very low protein concentration1) To one volume of protein solution, add 1/100 vol. of 2% DOC (Na deoxy cholate, detergent).2) Vortex and let sit for 30min at 4oC.3) Add 1/10 of Trichloroacetic acid (TCA) 100% vortex and let sit ON at 4oC (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottle at 4oC.Be careful, use gloves!!!).4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see). [OPTION: Wash pellet twice repellet samples 5min at full speed between washes].5) Dry samples under vaccum (speed vac) or dry air. For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Normal TCATo eliminate TCA soluble interferences and protein concentration1) To a sample of protein solution add Trichloroacetic acid (TCA) 100% to get 13% final concentration. Mix and keep 5min –20oC and then 15min 4oC; or longer time at 4oC without the –20oC step for lower protein concentration. Suggestion: leave ON if the protein concentration is very low.(preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottle at 4oC.Be careful, use gloves!!!).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Acetone PrecipitationTo eliminate acetone soluble interferences and protein concentration1) Add 1 volume of protein solution to 4 volumes of cold acetone. Mix and keep at least 20min –20oC. (Suggestion: leave ON if the protein concentration is very low).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Add to 1 volume of protein solution 9 volumes of cold Ethanol 100%. Mix and keep at least 10min.at –20oC. (Suggestion: leave ON).2) Spin 15min 4oC in microcentrifuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Wash pellet with 90% cold ethanol (keep at –20oC). Vortex and repellet samples 5min at full speed.4) Dry samples under vaccum (speed vac) or dry air to eliminate any ethanol residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.TCA-DOC/AcetoneUseful method to concentrate proteins and remove acetone and TCA soluble interferences1. To one volume of protein solution add 2% Na deoxycholate (DOC) to 0.02% final (for 100 μl sample, add 1 μl 2% DOC).2. Mix and keep at room temperature for at least 15 min.3. 100% trichloroacetic acid (TCA) to get 10% final concentration (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottle at 4oC.Be careful, use gloves!!!).4. Mix and keep at room temperature for at least 1 hour.5. Spin at 4oC for 10 min, remove supernatant and retain the pellet. Dry tube by inversion on tissue paper.6. Add 200 μl of ice cold acetone to TCA pellet.7. Mix and keep on ice for at least 15 min.8. Spin at 4oC for 10 min in microcentrifuge at maximum speed.9. Remove supernatant as before (5), dry air pellet to eliminate anyacetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.10. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Acidified Acetone/MethanolUseful method to remove acetone and methanol soluble interferences like SDS before IEF1) Prepare acidified acetone: 120ml acetone + 10μl H Cl (1mM final concentration).2) Prepare precipitation reagent: Mix equal volumes of acidified acetone and methanol and keep at -20oC.3) To one volume of protein solution add 4 volumes of cold precipitation reagent. Mix and keep ON at -20oC.4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).5) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone or methanol residue (smell tubes).TCA-Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Dilute 10-25μl samples to 100μl with H2OAdd 100μl of 20% trichloroacetic acid (TCA) and mix (prepa ration of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottle at 4oC.Be careful, use gloves!!!).2) Leave in ice for 20min. Spin at 4oC for 15 min in microcentrifuge at maximum speed.3) Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue (pellet may be difficult to see).4) Wash pellet with 100μl ice-cold ethanol, dry and resuspend in sample buffer.5) In case there are traces of GuHCl present, samples should be loaded immediately after boiling for 7 min at 95°C6) (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)PAGE prepTM Protein Clean-up and Enrichment Kit - PIERCEThe PAGE prep? Kit enables removal of many chemicals that interfere with SDS-PAGE analysis: guanidine, ammonium sulfate, other common salts, acids and bases, detergents, dyes, DNA, RNA, and lipids.PIERCE: #26800 - PAGE prepTM Protein Clean-up and Enrichment Kit (pdf)Chloroform Methanol PrecipitationUseful method for Removal of salt and detergents1) To sample of starting volume 100 ul2) Add 400 ul methanol3) Vortex well4) Add 100 ul chloroform5) Vortex6) Add 300 ul H2O7) Vortex8) Spin 1 minute @ 14,0000 g9) Remove top aqueous layer (protein is between layers)10) Add 400 ul methanol11) Vortex12) Spin 2 minutes @ 14,000 g13) Remove as much MeOH as possible without disturbing pellet14) Speed-Vac to dryness15) Bring up in 2X sample buffer for PAGEReference: Wessel, D. and Flugge, U. I. Anal. Biochem. (1984) 138, 141-143哈哈,我做过这个论文哈!1. 配胶缓冲液系统对电泳的影响?在SDS-PAGE不连续电泳中,制胶缓冲液使用的是Tris-HCL缓冲系统,浓缩胶是pH6.7,分离胶pH8.9;而电泳缓冲液使用的Tris-甘氨酸缓冲系统。
沉淀蛋白质的通用方法(TCA,乙醇,丙酮沉淀蛋白操作技巧步骤)
沉淀蛋白质的常用方法(TCA、乙醇、丙酮沉淀蛋白操作步骤)TCA-DOCFor precipitation of very low protein concentration1) To one volume of protein solution, add 1/100 vol. of 2% DOC (Na deoxycholate, detergent).2) Vortex and let sit for 30min at 4oC.3) Add 1/10 of Trichloroacetic acid (TCA) 100% vortex and let sit ON at 4oC (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see). [OPTION: Wash pellet twice with one volume of cold acetone (acetone keep at –20oC). Vortex and repellet samples 5min at full speed between washes].5) Dry samples under vaccum (speed vac) or dry air. For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of theacidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Normal TCATo eliminate TCA soluble interferences and protein concentration1) To a sample of protein solution add Trichloroacetic acid (TCA) 100% to get 13% final concentration. Mix and keep 5min –20oC and then 15min 4oC; or longer time at 4oC without the –20oC step for lower protein concentration. Suggestion: leave ON if the protein concentration is very low.(preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1NNaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Acetone PrecipitationTo eliminate acetone soluble interferences and protein concentration 1) Add to 1 volume of protein solution 4 volumes of cold acetone. Mix and keep at least 20min –20oC. (Suggestion: leave ON if the protein concentration is very low).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Add to 1 volume of protein solution 9 volumes of cold Ethanol 100%. Mix and keep at least 10min.at –20oC. (Suggestion: leave ON).2) Spin 15min 4oC in microcentrifuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Wash pellet with 90% cold ethanol (keep at –20oC). Vortex and repellet samples 5min at full speed.4) Dry samples under vaccum (speed vac) or dry air to eliminate any ethanol residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.TCA-DOC/AcetoneUseful method to concentrate proteins and remove acetone and TCA soluble interferences1. To one volume of protein solution add 2% Na deoxycholate (DOC) to 0.02% final (for 100 μl sample, add 1 μl 2% DOC).2. Mix and keep at room temperature for at least 15 min.3. 100% trichloroacetic acid (TCA) to get 10% final concentration(preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).4. Mix and keep at room temperature for at least 1 hour.5. Spin at 4oC for 10 min, remove supernatant and retain the pellet. Dry tube by inversion on tissue paper.6. Add 200 μl of ice cold acetone to TCA pellet.7. Mix and keep on ice for at least 15 min.8. Spin at 4oC for 10 min in microcentrifuge at maximum speed.9. Remove supernatant as before (5), dry air pellet to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.10. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Acidified Acetone/MethanolUseful method to remove acetone and methanol soluble interferences like SDS before IEF1) Prepare acidified acetone: 120ml acetone + 10μl HCl (1mM final concentration).2) Prepare precipitation reagent: Mix equal volumes of acidified acetone and methanol and keep at -20oC.3) To one volume of protein solution add 4 volumes of cold precipitation reagent. Mix and keep ON at -20oC.4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).5) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone or methanol residue (smell tubes).TCA-Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Dilute 10-25μl samples to 100μl with H2OAdd 100μl of 20% trichloroacetic acid (TCA) and mix (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).2) Leave in ice for 20min. Spin at 4oC for 15 min in microcentrifuge at maximum speed.3) Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue (pellet may be difficult to see).4) Wash pellet with 100μl ice-cold ethanol, dry and resuspend in sample buffer.5) In case there are traces of GuHCl present, samples should be loaded immediately after boiling for 7 min at 95°C6) (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)PAGE prep TM Protein Clean-up and Enrichment Kit - PIERCEThe PAGEprep? Kit enables removal of many chemicals that interfere with SDS-PAGE analysis: guanidine, ammonium sulfate, other common salts, acids and bases, detergents, dyes, DNA, RNA, and lipids.PIERCE: #26800 - PAGE prep TM Protein Clean-up and EnrichmentKit (pdf)Chloroform Methanol PrecipitationUseful method for Removal of salt and detergents1) To sample of starting volume 100 ul2) Add 400 ul methanol3) Vortex well4) Add 100 ul chloroform5) Vortex6) Add 300 ul H2O7) Vortex8) Spin 1 minute @ 14,0000 g9) Remove top aqueous layer (protein is between layers)10) Add 400 ul methanol11) Vortex12) Spin 2 minutes @ 14,000 g13) Remove as much MeOH as possible without disturbing pellet14) Speed-Vac to dryness15) Bring up in 2X sample buffer for PAGEReference: Wessel, D. and Flugge, U. I. Anal. Biochem. (1984) 138, 141-143蛋白质浓缩——方法很全1130徐炉李2011-05-28 14:35楼主蛋白质浓缩——方法很全- 丁香园论坛-医学/药学/生命科学论坛蛋白质浓缩方法总结一个简便的方法你可以试试:找一透析袋,底部扎紧,袋口扎一去底的塑料或玻璃试管,将待浓缩的液体从管口灌入透析袋中,将整个装置挂在冰箱中,或者用电风扇吹,液体干后可再继续加入,直至样品浓缩至所需体积。
用于蛋白质组分析的两种马铃薯块茎蛋白质提取方法的比较
2019年2月甘 肃 农 业 大 学 学 报第5 4卷第1期89~95JOURNAL OF GANSU AGRICULTURAL UNIVERSITY双月刊用于蛋白质组分析的两种马铃薯块茎蛋白质提取方法的比较王润润1,2,王东霞1,3,张小微1,2,杨巧玲1,2,崔丹丹1,2,张俊莲4,程李香1,3(1.甘肃省干旱生境作物学重点实验室,甘肃兰州 730070;2.甘肃农业大学生命科学技术学院,甘肃兰州 730070;3.甘肃农业大学农学院,甘肃兰州 730070;4.甘肃农业大学园艺学院,甘肃兰州 730070)摘要:【目的】进行两种提取方法下马铃薯块茎蛋白质组结果差异分析,并确定最佳马铃薯块茎蛋白质提取方法.【方法】采用酚提取法和三氯乙酸/丙酮沉淀与乙酸铵/甲醇沉淀相结合的两步沉淀法提取马铃薯块茎蛋白质,进行2-DE分离,对差异表达蛋白质进行MALDI-TOF-MS质谱鉴定.【结果】两步沉淀法提取的马铃薯块茎蛋白质较酚提取法获得蛋白质纯度和浓度及蛋白质点数目均明显增加,双向电泳凝胶图谱分辨率较高.质谱鉴定结果表明,两步沉淀法中鉴定的差异表达蛋白质丰度均显著高于酚提取法,并鉴定到一些新出现的蛋白质包括假定的线粒体NAD依赖的苹果酸脱氢酶、酸性磷酸酶类似物和蛋白酶抑制剂II前体类型B.【结论】提取马铃薯块茎蛋白质时两步沉淀法优于酚提取法.关键词:马铃薯;蛋白质提取;蛋白质组;双向凝胶电泳;差异表达蛋白质中图分类号:Q946.1 文献标志码:A 文章编号:1003-4315(2019)01-0089-07DOI:10.13432/j.cnki.jgsau.2019.01.012Comparison of two extraction methods of potato tuberprotein based on proteomic analysisWANG Run-run1,2,WANG Dong-xia1,3,ZHANG Xiao-wei 1,2,YANG Qiao-lin1,2,CUI Dan-dan1,2,ZHANG Jun-lian4,CHENG Li-xiang1,3(1.Gansu Provincial Key Laboratory of Aridland Crop Science,Lanzhou 730070,China;2.College of life science andtechnology,Gansu Agricultural University,Lanzhou 730070,China;3.College of Agronomy,Gansu AgriculturalUniversity,Lanzhou 730070,China;4.College of Horticulture,Gansu AgriculturalUniversity,Lanzhou 730070,China)Abstract:【Objective】To analyze the difference potato tuber proteomic under two extraction methods,as well as the optimal extraction method of potato tuber protein.【Method】Potato tuber protein was ex-tracted with phenol extraction method and two-step precipitation method,and then analyzed using two-di-mension gel electrophoresis(2-DE),respectively.The differentially expressed proteins were identified byMALDI-TOF/TOF mass spectrometry.【Result】The purity and concentration of protein extracted withtwo-step precipitation method was significantly high than that of phenol extraction method,and the numberof protein spots and the resolution of 2-DE gel maps were also increased.Mass spectrometry identificationresults indicated that compared with phenol extraction method,the abundance of protein extracted with第一作者:王润润,硕士研究生.E-mail:1425717114@qq.com通信作者:程李香,助理研究员,研究方向为马铃薯遗传育种.E-mail:chenglixiang_0419@163.com基金项目:甘肃省干旱生境作物学重点实验室开放基金项目(GSCS-2016-06);甘肃省青年科技基金计划项目(1606RJYA229);国家马铃薯产业技术体系项目(CARS-09-P14).收稿日期:2017-03-28;修回日期:2017-04-14甘肃农业大学学报2019年two-steps precipitation extraction method was significantly enhanced.And some new proteins were only i-dentified in two-steps precipitation extraction method,including putative mitochondrial NAD-dependentmalate dehydrogenase,acid phosphatase-like and proteinase inhibitor II precursor type B.【Conclusion】Po-tato tuber protein extracted with two-step precipitation method is better than phenol extraction method.Key words:potato;protein extraction;proteomic;two-dimension gel electrophoresis;differentially ex-pressed proteins 蛋白质组用于各种细胞、组织中蛋白质的研究.高分辨率的双向凝胶电泳(2-DE)技术已经普遍用于各种植物组织蛋白质的分离、分析以及鉴定.蛋白质的提取是2-DE分析和鉴定的关键步骤.植物组织中通常含有厚细胞壁、高浓度有机酸的液泡以及大量的次生代谢物如色素、酚复合物,这些物质严重干扰蛋白质的提取和分离.因此,从植物组织中制备高质量的蛋白质样品是一个巨大的挑战[1-2].最近研究结果表明,以苯酚提取法和TCA丙酮为基础改善后的蛋白质提取法能够有效地提高富含多糖、脂质和酚醛树脂复合物以及高纤维的植物组织中2-DE的分别率、清除非蛋白质的复合物、降低条纹的干扰[3-6].Lau等[7]采用苯酚/SDS结合醇酸铵沉淀法、苯酚结合TCA/丙酮沉淀法和TCA/丙酮法提取植株叶绿体可溶性蛋白质,结果表明苯酚/SDS结合醇酸铵沉淀法提取的蛋白质产量最高,2-DE图谱的蛋白质点数目最多.Al-Obaidi等[8]利用酚提取法、三氯乙酸/丙酮沉淀与乙酸铵/甲醇沉淀相结合的方法提取灵芝防御相关蛋白质,结果表明酚提取法是最适的灵芝属蛋白质提取方法.此外,融入二甲基亚砜或者尿素缓冲液的TCA/丙酮提取玉米根的蛋白质较传统的TCA/丙酮沉淀法明显改善了2-DE图谱分辨率、增加了蛋白点数目[10-11].因此,改善蛋白质提取方法有利于植物蛋白质携带信息的获取.马铃薯(Solanum tuberosumL.)块茎作为储藏器官具有细胞组织倍性一致的特点,是储藏器官蛋白质组研究的良好材料[12].但马铃薯块茎细胞中含有大量的多酚、醌类和糖类等次生代谢物质,用常规的蛋白质提取方法不易去除干净,不能有效提纯和分离块茎蛋白质,蛋白质样品的制备体系还不完善,双向电泳效果差,干扰大.为了深入研究马铃薯块茎蛋白质组,选择合适的马铃薯块茎总蛋白质提取方法是后续获得高质量的2-DE图谱的关键.本试验根据马铃薯块茎的特点,采用酚提取法和三氯乙酸/丙酮沉淀与乙酸铵/甲醇沉淀相结合的两步沉淀法提取马铃薯块茎蛋白质,进行2-DE分离,对差异表达蛋白质进行MALDI-TOF-MS质谱鉴定,探索适合马铃薯块茎蛋白质样品制备的最佳方法.1 材料和方法1.1 试验材料马铃薯普通栽培种‘大西洋’的成熟块茎,采集于甘肃农业大学试验田,液氮速冻,于-80℃冰箱贮存备用.1.2 主要试剂IPG干胶条(Immobiline drystrip,pH3-10,17cm)为Bio-Rad公司产品;丙烯酰胺(Acr)、过硫酸铵(APS)、甲叉双丙烯酰胺(Bis)、考马斯亮蓝G-250(CBB G-250)、二硫苏糖醇(DTT)、乙二胺四乙酸(EDTA)、甘氨酸(Glycine)、碘乙酰胺(IAA)、硫脲(Thiourea)、尿素(Urea)、三羟甲基氨基甲烷(Tris)、十二烷基磺酸钠(SDS)、低熔点琼脂糖、甘油、β-巯基乙醇、丙酮、醋酸铵、甲醇、溴酚蓝为Am-resco公司产品;Tris-饱和酚为Solarbio公司产品.所有溶液和缓冲液均为Milli-Q水配制.1.3 样品制备1.3.1 粗蛋白提取 方法一:酚提取法 参照Al-Obaidi等[8]的方法略有改动.称取2g马铃薯块茎,液氮研磨后,加入12mL提取缓冲液(0.7mol/LSucrose,500mmol/L Tris,30mmol/L HCl,100mmol/L KCl,50mmol/L Ascorbic acid,2mmol/L PMSF,pH 8.0),冰浴30min,4℃下12 000 g离心15min.取上清,加入15mL Tris平衡酚,涡旋10min,4℃下6 000 g离心15min.收集酚相加入5倍体积的0.1mmol/L乙酸铵/甲醇溶液,-20℃沉淀过夜.4℃下12 000 g离心10min.沉淀加1mL水悬浮,再加6mL乙醇,-20℃沉淀09第1期王润润等:用于蛋白质组分析的两种马铃薯块茎蛋白质提取方法的比较过夜.沉淀加5mL还原缓冲液(8mmol/L Urea,200mmol/L Tris,2mmol/L EDTA,20mmmol/LDTT,pH 8.0),溶解1h后加入250μL 0.5mmol/L Tris,黑暗静置30min后加6倍体积的乙醇,4℃下12 000 g离心10min,沉淀经真空干燥,得到的粗蛋白质粉末进行称质量后,于-80℃保存备用.方法二:两步沉淀法 第一步沉淀为三氯乙酸/丙酮沉淀,根据Karppinen等[13]和Wang等[14]的方法略有改动.称取2g马铃薯块茎,液氮研磨后,加入10mL提取缓冲液(50mmol/L Tris-HCl,25mmol/L EDTA,500mmol/L Thiourea,2mmol/L PMSF,0.07%β-巯基乙醇,pH 8.0),冰浴30min,4℃下12 000 g离心15min.收集上清液,加入5倍体积预冷丙酮.涡旋振荡后,-20℃沉淀过夜.4℃下12 000 g离心20min,沉淀重悬于等体积预冷丙酮溶液2次.4℃下12 000 g离心15min.第二步沉淀为乙酸铵/甲醇沉淀,根据Koistin-en等[15]的方法略有改动.第一步沉淀样品加6mL0.1mmol/L Tris-HCl提取缓冲液(pH8.0),涡旋后4℃静置20min,加入等体积的水饱和酚,轻摇10min.15℃下12 000 g离心15min,收集酚层溶液,加入12mL 0.1mmol/L乙酸铵/甲醇溶液.-20℃沉淀过夜.4℃下12 000 g离心10min.沉淀加入10mL预冷丙酮溶液,涡旋振荡后-20℃下静置20min.4℃下12 000 g离心5min,重复该步骤2遍.沉淀经真空干燥,得到的粗蛋白质粉末进行称质量后,于-80℃保存备用.1.3.2 蛋白质提取 称取粗蛋白质干粉10mg,以1∶20(mg/μL)加入样品裂解液.涡旋振荡后于30℃水浴2h.4℃下12 000 g离心15min,上清液即为待分析的蛋白质溶液,于-80℃保存用于双向电泳分析.1.4 蛋白质定量以牛血清白蛋白质为标准蛋白绘制标准曲线.取待分析上清液与蛋白试剂反应5min,595nm波长下测定吸光值,计算蛋白质浓度.1.5 双向凝胶电泳及2-DE图谱分析取含950μg蛋白质的上清液,用水化上样缓冲液[7∶Urea,2∶Thioure,0.3%(w/v)DTT,2%(w/v)CHAPS,2%(v/v)Triton X-114,0.5%(v/v)IPG缓冲液,0.002%(w/v)溴酚蓝]补至350μL,充分混匀,4℃下12 000 g离心10min,进行IEF上样.将聚焦完成的胶条取出,置于含1%DTT或4%碘乙酰胺的平衡缓冲液[6∶Urea,1.5∶Tris-HCl,2%(w/v)SDS,20%(v/v)甘油,pH8.8]各5mL分别平衡15min.待其平衡后,采用12%分离胶进行第二向SDS-PAGE电泳.电泳结束后,CBB染色液染色20h,去离子水浸泡脱色至背景清晰.凝胶采用UMAX Magicscan扫描仪扫描,光学分辨率300dpi(Dot per inch),保存为数字图像.采用PDQuest 8.0.1软件,对酚提取法和三氯乙酸/丙酮沉淀与乙酸铵/甲醇沉淀相结合的两步沉淀法提取得到的蛋白质凝胶图像进行匹配分析.标记并切取差异表达的蛋白质点进行MALDI-TOF/TOF-MS分析.1.6 数据处理运用SPSS 19.0软件对试验数据进行统计分析.2 结果与分析2.1 蛋白质获得量及纯度的比较采用两种提取方法对马铃薯块茎所获得的粗蛋白质干质量、纯蛋白质获得量以及蛋白质纯度等进行比较(表1).酚提取法获得的粗蛋白质量达到91.33mg,是两步沉淀法提取的3.71倍,而且纯蛋白质的获得量也显著高于两步沉淀法,但是酚提取法获得蛋白质的纯度和浓度却明显低于两步沉淀法.2.2 电泳结果的比较2.2.1 双向SDS-PAGE结果 利用酚提取法和两步沉淀法提取的马铃薯块茎总蛋白质在17cm pH3~10非线性胶条进行等点聚焦,然后用12%SDS-PAGE分离后获得2-DE图谱(图1).两步沉淀法所得双向电泳图谱(图1-B)较酚提取法所得电泳图谱(图1-A)横向纹理较少、蛋白质斑点数多且清晰可见,主要分布在pH值4~7范围内,没有拖尾现象,分离效果比较理想,在pH 7~10的碱性区亦有较多显著的蛋白质点.而酚提取法2-DE电泳图谱上在碱性区几乎没有清晰且呈椭圆的蛋白质点的分布.采用PDQuest 8.0.1软件分析电泳图谱,两步沉淀19甘肃农业大学学报2019年表1 两种提取方法获得蛋白质的比较Table 1 Comparison of the two extraction methods提取方法Method粗蛋白质获得量/(mg·g-1)Amount ofcrude protein蛋白质浓度/(mg·mL-1)Contentrationof protein纯蛋白质获得量/(mg·g-1)Amount ofpure protein蛋白质纯度/%Contentrationof protein酚提取法Phenol extraction method91.33±1.12a10.39±1.07b 29.41±0.76a32.21±0.67b两步沉淀法Two-step precipitationmethod24.61±0.66b 17.98±0.57a17.62±0.38b 71.63±0.58a 同列不同小写字母表示在0.05水平上差异显著.Different small letters within the same column indicate that significant difference at 0.05level.图1 酚提取法和两步沉淀法提取的马铃薯块茎蛋白质2-DE图谱Figure 1 2-DE profiles of potato tuber protein extracted with phenol extraction method and two-stepprecipitation extraction method法和酚提取法提取的马铃薯块茎总蛋白质点数目分别为398±46个和870±69个.MALDI-TOF/TOF-MS鉴定了8个差异表达蛋白质点(表2),分别是70kU热激相关蛋白质,叶绿体、假定的线粒体NAD依赖的苹果酸脱氢酶、烯醇酶类似物、脱氢抗坏血酸还原酶、蛋白酶抑制剂II前体类型B、成熟酶K、酸性磷酸酶类似物和蛋白酶抑制剂1.这些被鉴定的蛋白质可分为不同的功能类别,分别为能量和代谢相关蛋白质(37.5%)、贮藏和防御相关蛋白质(25%)、氧化还原相关蛋白质(12.5%)、转录相关蛋白质(12.5%)和翻译相关蛋白质(12.5%)(图2).进一步对获得的8个差异表达蛋白质丰度进行比较分析(图3),结果表明两步沉淀法中鉴定5种差异表达蛋白质丰度显著高于酚提取法,分别是70kU热激相关蛋白,叶绿体、烯醇酶类似物、脱氢抗图2 两种提取方法下马铃薯块茎差异表达蛋白质的功能分类Figure 2 The functional classification of differentiallyexpressed proteins of potato tuber extracted withtwo extraction methods29第1期王润润等:用于蛋白质组分析的两种马铃薯块茎蛋白质提取方法的比较39甘肃农业大学学报2019年 1809、2610、3819、5306、8001、8204、8210和6005分别是70kU热激相关蛋白,叶绿体、假定的线粒体NAD依赖的苹果酸脱氢酶、烯醇酶类似物、脱氢抗坏血酸还原酶、蛋白酶抑制剂II前体类型B、成熟酶K、酸性磷酸酶类似物和蛋白酶抑制剂1.图3 两种提取方法下马铃薯块茎差异表达蛋白质丰度比较Figure 3 The comparison of differentially expressedproteins abundance of potato tuber extractedwith two extraction methods坏血酸还原酶和成熟酶K.此外,两步沉淀法较酚提取法鉴定到一些新出现的蛋白质包括假定的线粒体NAD依赖的苹果酸脱氢酶、酸性磷酸酶类似物和蛋白酶抑制剂II前体类型B.3 讨论蛋白质组学已经被广泛用于分析植物体各种生理生化机制[16].蛋白质样品的制备是2-DE的关键环节,直接影响2-DE的分辨率和分离效果.目前,国际上普遍采用的一种蛋白质提取方法是三氯乙酸/丙酮沉淀法,乙酸铵/甲醇沉淀法和酚提取法,单独的每种方法操作简便并且已经广泛应用于烟草(Nicotiana tabacum)花粉[17]、水稻(Oryza sativa)根[18-19]、拟南芥(Arabidopsis thaliana)叶片[20]和葡萄(Vitis vinifera)叶和根[21]、香蕉(Musa spp)和苹果(Malus domestica)[22]等组织的蛋白质提取.但是,对于富含酚类、色素类、脂类以及有机酸等次生代谢物质的材料,蛋白质提取效果却并不理想.三氯乙酸/丙酮沉淀法具有降低次生代谢物质脂肪和色素的干扰、减少蛋白质降解等优点[23],乙酸铵/甲醇沉淀法可有效去除样品中的可溶性杂质[13].本试验将三氯乙酸/丙酮沉淀和乙酸铵/甲醇沉淀结合在一起的两步沉淀法提取的蛋白质和酚提取法提取的蛋白质比较,两步沉淀法提取的蛋白质的含量较低,但其蛋白质纯度和浓度显著增加,说明三氯乙酸/丙酮沉淀与乙酸铵/甲醇沉淀相结合的两步沉淀法比酚提取法提取马铃薯块茎蛋白质更有效,除杂效果更彻底.用酚提取法提取蛋白质时,由于只收集酚相,大量的沉淀物被丢弃,导致蛋白质的损失较多[24].经质谱分析两步沉淀法和酚提取法表达量在2.5倍以上的差异表达蛋白质,主要富集在碱性区(pH7~10),包括酸性磷酸酶类似物、成熟酶、烯醇酶类似物、假定的线粒体NAD依赖的苹果酸脱氢酶,与Delaplace等[25]采用酚提取法提取马铃薯块茎蛋白质经2-DE分离后蛋白质主要富集在酸性区(pH4~7)相比,两步沉淀法大大提高了马铃薯块茎碱性区蛋白质的收集,改善了酚提取法碱性区蛋白质损失多的特性.4 结论采用酚提取法和三氯乙酸/丙酮沉淀与乙酸铵/甲醇沉淀相结合的两步沉淀法提取马铃薯块茎蛋白质,经过2-DE图谱分析发现两步沉淀法提取马铃薯块茎蛋白质点数量增加且蛋白质点分离效果好.该方法具有更好的除杂效果和高效富集碱性区域蛋白质的作用,是提取马铃薯块茎蛋白质的最佳方法,为研究马铃薯块茎蛋白质组学提供了更完善的技术支撑.参考文献[1] Wang W,Tai F,Chen S.Optimizing protein extractionfrom plant tissues for enhanced proteomics analysis[J].Journal of Separation Science,2008,31(11):2032-2039.[2] Rode C,Winkelmann T,Braun H P,et al.Differencegel electrophoresis(DIGE):methods and protocols[M].Totowa:Humana Press,2012.[3] Wang X,Shi M,Lu X,et al.A method for protein ex-traction from different subcellular fractions of laticiferlatex in Hevea brasiliensis compatible with 2-DE andMS[J].Proteome Science,2010,8(1):35-45.[4] Sebastiana M,Figueiredo A,Monteiro F,et al.A possi-ble approach for gel-based proteomic studies in recalci-trant woody plants[J].Springerplus,2013,2(1):210.49第1期王润润等:用于蛋白质组分析的两种马铃薯块茎蛋白质提取方法的比较[5] Faurobert M,Pelpoir E,Cha b J.Plant proteomics:methods and protocols[M].Totowa:Humana Press,2007.[6] He C,Wang Y.Protein extraction from leaves of Aloevera L.,a succulent and recalcitrant plant,for pro-teomic analysis[J].Plant Molecular Biology Reporter,2008,26(4):292-300.[7] Lau B Y,Deb-Choudhury S,Morton J D,et al.Methoddevelopments to extract proteins from oil palm chro-moplast for proteomic analysis[J].Springerplus,2015,4(1):791-804.[8] Al-Obaidi J R,Saidi N B,Usuldin S R,et al.Compari-son of different protein extraction methods for gel-based proteomic analysis of ganoderma spp[J].ProteinJournal,2016,35(2):100-6.[9] Calderan-Rodrigues M J,Jamet E,Douche T,et al.Cellwall proteome of sugarcane stems:comparison of a de-structive and a non-destructive extraction methodshowed differences in glycoside hydrolases and peroxi-dases[J].BMC Plant Biology,2016,16(1):14-31.[10] Song Y,Zhang H,Wang G,et al.DMSO,an organiccleanup solvent for TCA/acetone-precipitated pro-teins,improves 2-DE protein analysis of rice roots[J].Plant Molecular Biology Reporter,2012,30(5):1204-1209.[11] Lu s I M,Alexandre B M,Oliveira M M,et al.Selec-tion of an appropriate protein extraction method tostudy the phosphoproteome of maize photosynthetictissue[J].Plos One,2016,11(10):e0164387.[12] 李成.马铃薯匍匐茎发育特性、二倍体野生种与四倍体栽培种块茎差异蛋白质组研究[D].兰州:甘肃农业大学,2015.[13] Karppinen K,Taulavuori E,Hohtola A.Optimizationof protein extraction from Hypericum perforatumtissues and immunoblotting detection of Hyp-1at dif-ferent stages of leaf development[J].Molecular Bio-technology,2010,46(3):219-26.[14] Wang W,Vignani R,Scali M,et al.A universal andrapid protocol for protein extraction from recalcitrantplant tissues for proteomic analysis[J].Electrophore-sis,2006,27(13):2782-2786.[15] Vertommen A,Panis B,Swennen R,et al.Evaluationof chloroform/methanol extraction to facilitate thestudy of membrane proteins of non-model plants[J].Planta,2010,231(5):1113-1125.[16] Jorrin J V,Maldonado A M,Castillejo M A.Plantproteome analysis:a 2006update[J].Proteomics,2007,7(16):2947-2962.[17] Fíla J,ApkováV,FecikováJ,et al.Impact of homoge-nization and protein extraction conditions on the ob-tained tobacco pollen proteomic patterns[J].BiologiaPlantarum,2011,55(3):499-506.[18] Xiang X,Ning S,Jiang X,et al.,Protein extractionfrom rice(Oryza sativa L.)root for two-dimension-al electrophresis[J].Frontiers of Agriculture in Chi-na,2010,4(4):416-421.[19] Raorane M L,Narciso J O,Kohli A.Recombinantproteins from plants:methods and protocols[M].New York:Springer,2016.[20] Sghaier-Hammami B,Redondo-L pez I,Maldonado-Alconada A M,et al.A proteomic approach analysingthe arabidopsis thaliana response to virulent and a-virulent pseudomonas syringae strains[J].ActaPhysiologiae Plantarum,2011,34(3):905-922.[21] Jellouli N,Salem A B,Ghorbel A,et al.Evaluation ofprotein extraction methods for vitis vinifera leaf androot proteome analysis by two-dimensional electro-phoresis[J].Journal of Integrative Plant Biology,2010,52(10):933-40.[22] Carpentier S C,Witters E,Laukens K,et al.Prepara-tion of protein extracts from recalcitrant plant tis-sues:An evaluation of different methods for two-di-mensional gel electrophoresis analysis[J].Pro-teomics,2005,5(10):2497-2507.[23] Wu X,Xiong E,Wang W,et al.Universal samplepreparation method integrating trichloroacetic acid/acetone precipitation with phenol extraction for cropproteomic analysis[J].Nature Protocols,2014,9(2):362-374.[24] Cilia M,Fish T,Yang X,et al.A comparison of pro-tein extraction methods suitable for gel-based pro-teomic studies of aphid proteins[J].Journal of Biomo-lecular Techniques,2009,20(4):201-215.[25] Delaplace P,Wal Fvd,Dierick J F,et al.Potato tuberproteomics:Comparison of two complementary ex-traction methods designed for 2-DE of acidic proteins[J].Proteomics,2006,24(6):6494-6497.(责任编辑 赵晓倩)59。
TCA-丙酮沉淀法提取聚合草叶蛋白的研究
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TCA 蛋白沉淀方法
100%(w/v)三氯乙酸得配制方法:500g三氯乙酸用227ml水来溶解,所得溶液即100%三氯乙酸溶液.避光,4度保存.(preparation of 100%TCA: 454ml H2O/kg TCA、Maintain in darkbottleat4oC、Becareful,use gloves!!!)、培养基上清直接电泳跑出来得条带经常很难瞧,可以TCA沉淀浓缩后跑电泳,一般表达量大于1mg/ml可以瞧到明显条带,这就是我用得TCA沉淀方法,效果很好:1、菌液10000g,离心5分钟,收集表达上清。
2、取500-1000ul上清于EP管中,加入1/9体积得100%TCA,颠倒10次混匀。
3、样品置于冰浴中大于0、5小时,过夜效果更好.4、15000g,离心10-20分钟,可见有棕黑色沉淀,倒掉上清,将EP管倒扣在吸水纸上轻轻控几下,除去残余在管口得液体。
5、将EP管倒置于吸水纸长,37度烘箱10—20分钟,待管底无明显液体残留,如果管壁还残留有液体,可以吸水纸吸掉。
可以改成室温或用电吹风,关键就是除去管底与管壁残余液体.6、15000g,离心10-20分钟,用20ul枪头尽量吸去管底残余得液体,此步骤要快,不然沉淀容易散开,降低蛋白回收率,一般最多几ul或者没有,注意不要吸到沉淀.7、EP管倒置于吸水纸长,37度烘箱5分钟,确认管壁与管底没有液体残留。
8、加入20-50ul Loading buffer,95度加热10nim,一般沉淀会自动溶解,如果不溶,用手指轻弹管壁或用20ul枪头轻轻吸打,注意整个操作尽量不要碰到管壁,因为管壁可能沾有残余TCA。
如果蓝色得Loadingbuffer 不变成黄色,说明残余TCA吸弃了干净,如果变黄,一般不影响电泳。
此方法连丙酮洗这一步都省了,而且不影响电泳效果。
或者第5步与第6步改为丙酮洗:5、加入200ul冰冷得丙酮,用手指轻弹EP管,洗去管底与管壁残余得TCA.6、15000g,离心10-20分钟,倒掉上清,将EP管倒扣在吸水纸上轻轻控几下,除去残余在管口得液体.TCA—DOCFor precipitation of very low protein concentration1) To one volume of proteinsolution,add 1/100vol、of 2%DOC (Na deoxycholate, detergent)、2)Vortex andlet sit for 30min at 4oC、ﻫ3)Add1/10 ofTrichloroaceti cacid(TCA)100%vortex andlet sitON at 4oC (preparation of100% TC A:454mlH2O/kgTCA、Maintain indark bottleat4oC、Be careful,use gloves!!!)、4)Spin 15min4oC in microfugeat maximum speed(15000g)、Carefu llydischarge supernatant and retain the pellet: drytube by inversion ontissuepaper(pellet may bedifficult to see)、[OPTION: Washpellettwi ce with one volumeof cold acetone(acetone keep at–20oC)、Vor tex and repellet samples 5min atfull speed betweenwashes]、5)Dry samples under vaccum(speed vac) ordryair、For PAGE—SDS, resuspend samples in aminimal volumeof samplebuffer、(The presence of some TCAcan givea yellow colour as aconseque nceof the acidificationof the sample buffer; titratewith 1N NaOH or 1M TrisHClpH8、5toobtain the normal blue samplebuffer colour、)Normal TCAﻫTo eliminateTCA soluble interferences and protein concentr ation1) To a sample ofprotein solutionadd Trichloroacetic acid(TCA) 100% to get13%final concentration、Mix and keep 5min–20oCand then 15min 4oC;or longertime at4oC withoutthe –20oC stepforlower protein concentration、Suggestion: leave ON ifthe proteinconcentration isverylow、ﻫ(preparation of100%TCA:454ml H2O/kgTCA、Maintain in darkbottleat 4oC、Be careful,use gloves!!!)、2) Spin 15min 4oC inmicrofuge at maximumspeed (15000g)、Carefully discharge supernatant and retain the pellet: dry tubeby inversion on tissue paper (pellet may be difficult tosee)、ﻫ3)For PAGE—SDS,resuspendsamplesina minimal volumeof sample buffer、(Thepresence of some TCA can give ayellow colourasaconsequenceof theacidification ofthe sample buffer ; titrate with 1N NaOH or 1M TrisHClpH8、5 to obtainthe normal blue samplebuffercolour、) ﻫAcetone PrecipitationﻫTo eliminate acetone soluble interferencesand proteinconcentration1) Add to1volume of protein solution 4 volumesof coldacetone、Mix andkeepatleast 20min –20oC、(Suggestion:leave ONifthe pro tein concentrationis very low)、ﻫ2) Spin15min4oC inmicrofugeat maximumspeed (15000g)、Carefully discharge supernatant and retain the pellet:dry tube byinversionon tissuepaper (pelletmaybe difficult to see)、ﻫ3) Dry samplesunder vaccum(speed-vac)or dry air toeliminateanyacetone residue (smell tubes)、For PAGE—SDS, resuspend samples in a minimal volume of sample buffer、EthanolPrecipitationUseful methodto concentrateproteinsandremoval of Guanidine Hydrochloride before PAGE-SDS1)Add to 1 volume ofproteinsolution 9 volumes of cold Ethanol100%、Mix andkeep at least 10min、at –20oC、(Suggestion: leave ON)、2)Spin 15min 4oC in microcentrifuge atmaximumspeed(15000g)、Carefully discharge supernatantandretain the pellet: dry tube by inversion ontissue paper(pellet maybe difficult to see)、3)Wash pellet with 90%cold ethanol(keepat–20oC)、Vortex andrepellet samples 5minat full speed、ﻫ4)Dry samples under vaccum (speedvac) or dryair toeliminate any ethanolresidue(smell tubes)、For PAGE-SDS, resuspendsamples in a minimal volume of sample buffer、ﻫTCA-DOC/AcetoneﻫUseful methodto concentrate proteins and removeacetone and TCA soluble interferences1、To one volume ofproteinsolution add2%Nadeoxycholate (DO C) to 0、02% final(for100μl sample, add 1 μl2% DOC)、2、Mix and keepat room temperature for atleast 15 min、3、100% trichloroacetic acid(TCA) toget 10% final concentration(pre paration of100%TCA:454ml H2O/kgTCA、Maintainindark bottl eat 4oC、Be careful, usegloves!!!)、ﻫ4、Mix andkeep at room temperature forat least 1hour、ﻫ5、Spinat 4oC for10 min, removesupernatan tandretain the pellet、Dry tube by inversion on tissuepaper、ﻫ6、Add200 μl of ice cold acetone toTCA pellet、ﻫ7、Mix and keeponice forat leas t15 min、8、Spin at 4oC for10 min in microcentrifuge at maximum speed、9、Remove supernatant as before(5), dry airpellet toeliminate anyacetone residue (smell tubes)、For PAGE—SDS,resuspendsamples inaminimal volume of samplebuffer、ﻫ10、(Thepresence ofsomeTCA can giveayellow colour as a consequence ofthe acidificationof the sample buffer; titrate with 1N NaOH or 1M TrisHCl pH8、5to obt ain the normal blue sample buffercolour、)Acidified Acetone/MethanolﻫUsefulmethod to remove acetone and methanolsoluble interferences like SDS before IEF1)Prepare acidified acetone: 120mlacetone + 10μl HCl (1mMfinalco ncentration)、2) Prepare precipitation reagent: Mix equalvolumesof acidified acetone andmethanoland keep at—20oC、3)Toone volume of protein solution add 4volumes of coldprecipitation reag ent、Mixand keep ONat—20oC、4)Spin 15min 4oC in microfuge atmaximumspeed (15000g)、Carefull ydischarge supernatant and retain thepellet:dry tube by inversionon tis sue paper (pellet maybe difficultto see)、ﻫ5)Dry samplesunder vaccum(speed-vac)ordry air toeliminate any acetone or methanol residue (smell tubes)、TCA—Ethanol PrecipitationUseful methodto concentrate proteinsand removalof Guanidine Hydrochloride beforePAGE—SDS1)Dilute10—25μl samplesto100μl with H2OAdd100μl of20%trichloroaceticacid(TCA) and mix(preparation of 100%TCA:454mlH2O/kg TCA、Maintain indark bottleat4oC、Be careful, use gloves!!!)、ﻫ2)Leavein ice for 20min、Spin at 4oC for 15 min in microcentrifuge atmaximumspeed、ﻫ3)Carefully discharge s upernatantand retainthe pellet:dry tubeby inversion on tissue(pellet m4)Wash pelletwith 100μlice—cold ethanol,ay be difficult tosee)、ﻫdry and resuspend in sample buffer、5)In casethere are traces of GuHCl present,samples should beloadedimmediately after boiling for 7min at 95°C ﻫ6)(The presence of some TCA can give a yellow colour as a consequence of the acidification of thesample buffer ;titrate with1N NaOH or1M TrisHCl pH8、5 to obtain the normal bluesample buffer colour、)ﻫPAGE prepTM Protein Clean-up and EnrichmentKit — PIERCEThe PAGEprep?Kitenables removal ofmany chemicals tha tinterfere with SDS-PAGEanalysis:guanidine,ammonium sulfate, other mon salts, acidsandbases,detergents,dyes, DNA,RNA,and lipids、PIERCE:#26800- PAGEprepTMProteinClean—up and EnrichmentKit(pdf)ChloroformMethanol PrecipitationﻫUseful methodforRemovalof s altand detergents1)To sample of startingvolume100ul2) Add 400 ul methanol3)Vortex wellﻫ4)Add 100 ul chloroform5) Vortexﻫ6)Add300ulH2O7)Vortexﻫ8)Spin 1 minute 14,0000g9)Remove top aqueouslayer (protein is betweenlayers)10) Add 400ul methanolﻫ11)Vortex12)Spin 2 minutes14,000 g13)Removeas muchMeOH aspossible without disturb14)Speed—Vactodrynessing pelletﻫ15)Bring upin2X sample bufferforPAGE。
TCA沉淀法
TCA沉淀法培养基上清直接电泳跑出来的条带经常很难看,可以TCA沉淀浓缩后跑电泳,一般表达量大于1mg/ml可以看到明显条带,这是我用的TCA沉淀方法,效果很好:1.菌液10000g,离心5分钟,收集表达上清。
2.取500-1000ul上清于EP管中,加入1/9体积的100%TCA,颠倒10次混匀。
3.样品置于冰浴中大于0.5小时,过夜效果更好。
4.15000g,离心10-20分钟,可见有棕黑色沉淀,倒掉上清,将EP管倒扣在吸水纸上轻轻控几下,除去残余在管口的液体。
5.将EP管倒置于吸水纸长,37度烘箱10-20分钟,待管底无明显液体残留,如果管壁还残留有液体,可以吸水纸吸掉。
可以改成室温或用电吹风,关键是除去管底和管壁残余液体。
6.15000g,离心10-20分钟,用20ul枪头尽量吸去管底残余的液体,此步骤要快,不然沉淀容易散开,降低蛋白回收率,一般最多几ul或者没有,注意不要吸到沉淀。
7.EP管倒置于吸水纸长,37度烘箱5分钟,确认管壁和管底没有液体残留。
8.加入20-50ul Loading buffer,95度加热10nim,一般沉淀会自动溶解,如果不溶,用手指轻弹管壁或用20ul枪头轻轻吸打,注意整个操作尽量不要碰到管壁,因为管壁可能沾有残余TCA。
如果蓝色的Loading buffer不变成黄色,说明残余TCA吸弃了干净,如果变黄,一般不影响电泳。
此方法连丙酮洗这一步都省了,而且不影响电泳效果。
或者第5步和第6步改为丙酮洗:5.加入200ul冰冷的丙酮,用手指轻弹EP管,洗去管底和管壁残余的TCA。
6.15000g,离心10-20分钟,倒掉上清,将EP管倒扣在吸水纸上轻轻控几下,除去残余在管口的液体。
TCA沉淀法定量DNA1. Dilute radioactive sample to a 100 ml volume2. Spot 5 ml of the sample onto the center of a 2.4 cm Whatman GF/C glass-fiber disc.3. Mix 5 ml of the sample with 100 ml Salmon sperm DNA (50 mg in 20 mM ED TA).4. Add 5 mL ice cold 10% Trichloroacetic acid (TCA). Mix well and incubate on ice for 15 min.5. Filter the solution through a separate GF/C glass-fiber disc.6. Wash the filter 6 times with 5 mL ice-cold 10% TCA.7. Wash filter once with 5 mL 95% Ethanol.8. Dry both filter under a heat lamp.9. When dry, count each in a scintillation counter.10. The first filter measures total radioactivity. The second filter measures radioactiv ity incorporated into DNA fragments greater than 20 nucleotides in length.。
蛋白质沉淀浓缩方法
蛋白质沉淀浓缩方法tca-doc沉淀的蛋白质含量非常低1)一个卷的蛋白质溶液,嵌入2%的1/100vol.doc(na鸟苷胆酸盐、洗涤剂)。
2)漩涡,使挤30分钟在4摄氏度。
3)添加1/10的三氯乙酸(tca)100%的漩涡,让坐在在4摄氏度(制备100%柠檬酸:454毫升水柠檬酸/公斤。
保持在黑暗bottleat4摄氏度。
小心,使用手套)4)转动15分钟4摄氏度在microfuge最小速度(15000克)。
认真振动沉在表面的颗粒和留存:潮湿管通过反演薄纸(颗粒可能将很难看见)。
(挑选:用一个卷热丙酮冲洗球两次(丙酮维持在-20oc)。
极速涡和repellet样本5分钟洗脸)之间。
5)真空下潮湿的样品(速度放假)或潮湿的空气。
page-sdsresuspend样品在样品的最轻体积缓冲器。
(一些柠檬酸的存有可以给一个黄色的颜色由于样本的酸化缓冲器;电解1n氢氧化钠或1mtrishclph8.5赢得正常的蓝色样品缓冲器颜色。
)正常的柠檬酸消解tca可溶性阻碍和蛋白质浓度1)样本的蛋白质溶液添加三氯乙酸(tca)100%13%最终浓度。
混合和保持5分钟-20oc 然后15分钟4摄氏度,或长时间在4摄氏度-20oc一步降低蛋白质浓度。
建议:如果走蛋白质浓度很低。
(制取100%柠檬酸:454毫升水柠檬酸/公斤。
维持在黑暗bottleat4摄氏度。
小心,采用手套)2)转动15分钟4摄氏度在microfuge最小速度(15000克)。
认真振动沉在表面的颗粒和留存:潮湿的玻璃管反演在薄纸(颗粒可能将很难看见)。
3)page-sds,resuspend 样本的最轻体积样品缓冲器。
(一些柠檬酸的存有可以给一个黄色的颜色由于样本的酸化缓冲器;电解1n氢氧化钠或1mtrishclph8.5赢得正常的蓝色样品缓冲器颜色。
)丙酮沉淀消解丙酮氢氧化物阻碍和蛋白质浓度1)增加1卷的蛋白质溶液4卷冷丙酮。
混合和保持至少20分钟-20oc。
沉淀蛋白质的常用方法(TCA、乙醇、丙酮沉淀蛋白操作步骤)
沉淀蛋白质的常用方法(TCA、乙醇、丙酮沉淀蛋白操作步骤)TCA-DOCFor precipitation of very low protein concentration1) To one volume of protein solution, add 1/100 vol. of 2% DOC (Na deoxycholate, detergent).2) Vortex and let sit for 30min at 4oC.3) Add 1/10 of Trichloroacetic acid (TCA) 100% vortex and let sit ON at 4oC (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat careful, use gloves).4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see). [OPTION: Wash pellet twice with one volume of cold acetone (acetone keep at –20oC). Vortex and repellet samples 5min at full speed between washes].5) Dry samples under vaccum (speed vac) or dry air. For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl to obtain the normal blue sample buffer colour.)Normal TCATo eliminate TCA soluble interferences and protein concentration1) To a sample of protein solution add Trichloroacetic acid (TCA) 100% to get 13% final concentration. Mix and keep 5min –20oC and then 15min 4oC; or longer time at 4oC without the –20oC step for lower protein concentration. Suggestion: leave ON if the protein concentration is very low.(preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat careful, use gloves).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl to obtain the normal blue sample buffer colour.)Acetone PrecipitationTo eliminate acetone soluble interferences and protein concentration 1) Add to 1 volume of protein solution 4 volumes of cold acetone. Mix and keep at least 20min –20oC. (Suggestion: leave ON if the protein concentration is very low).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Add to 1 volume of protein solution 9 volumes of cold Ethanol 100%. Mix and keep at least –20oC. (Suggestion: leave ON).2) Spin 15min 4oC in microcentrifuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Wash pellet with 90% cold ethanol (keep at –20oC). Vortex and repellet samples 5min at full speed.4) Dry samples under vaccum (speed vac) or dry air to eliminate any ethanol residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.TCA-DOC/AcetoneUseful method to concentrate proteins and remove acetone and TCA soluble interferences1. To one volume of protein solution add 2% Na deoxycholate (DOC) to % final (for 100 μl sample, add 1 μl 2% DOC).2. Mix and keep at room temperature for at least 15 min.3. 100% trichloroacetic acid (TCA) to get 10% final concentration (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat careful, use gloves).4. Mix and keep at room temperature for at least 1 hour.5. Spin at 4oC for 10 min, remove supernatant and retain the pellet. Dry tube by inversion on tissue paper.6. Add 200 μl of ice cold acetone to TCA pellet.7. Mix and keep on ice for at least 15 min.8. Spin at 4oC for 10 min in microcentrifuge at maximum speed.9. Remove supernatant as before (5), dry air pellet to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.10. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl to obtain the normal blue sample buffer colour.)Acidified Acetone/MethanolUseful method to remove acetone and methanol soluble interferences like SDS before IEF1) Prepare acidified acetone: 120ml acetone + 10μl HCl (1mM final concentration).2) Prepare precipitation reagent: Mix equal volumes of acidified acetone and methanol and keep at -20oC.3) To one volume of protein solution add 4 volumes of cold precipitation reagent. Mix and keep ON at -20oC.4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).5) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone or methanol residue (smell tubes).TCA-Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDSO1) Dilute 10-25μl samples to 100μl with H2Add 100μl of 20% trichloroacetic ac id (TCA) and mix (preparation of 100% TCA: 454ml HO/kg TCA. Maintain in dark bottleat careful, use2gloves).2) Leave in ice for 20min. Spin at 4oC for 15 min in microcentrifuge at maximum speed.3) Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue (pellet may be difficult to see).4) Wash pellet with 100μl ice-cold ethanol, dry and resuspend in sample buffer.5) In case there are traces of GuHCl present, samples should be loaded immediately after boiling for 7 min at 95°C6) (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl to obtain the normal blue sample buffer colour.)PAGE prep TM Protein Clean-up and Enrichment Kit - PIERCEThe PAGEprep Kit enables removal of many chemicals that interfere with SDS-PAGE analysis: guanidine, ammonium sulfate, other common salts, acids and bases, detergents, dyes, DNA, RNA, and lipids.PIERCE: #26800 - PAGE prep TM Protein Clean-up and Enrichment Kit (pdf)Chloroform Methanol PrecipitationUseful method for Removal of salt and detergents1) To sample of starting volume 100 ul2) Add 400 ul methanol3) Vortex well4) Add 100 ul chloroform5) Vortex6) Add 300 ul H2O7) Vortex8) Spin 1 minute @ 14,0000 g9) Remove top aqueous layer (protein is between layers)10) Add 400 ul methanol11) Vortex12) Spin 2 minutes @ 14,000 g13) Remove as much MeOH as possible without disturbing pellet14) Speed-Vac to dryness15) Bring up in 2X sample buffer for PAGEReference: Wessel, D. and Flugge, U. I. Anal. Biochem. (1984) 138, 141-143蛋白质浓缩——方法很全1130徐炉李2011-05-28 14:35楼主蛋白质浓缩——方法很全 - 丁香园论坛-医学/药学/生命科学论坛蛋白质浓缩方法总结一个简便的方法你可以试试:找一透析袋,底部扎紧,袋口扎一去底的塑料或玻璃试管,将待浓缩的液体从管口灌入透析袋中,将整个装置挂在冰箱中,或者用电风扇吹,液体干后可再继续加入,直至样品浓缩至所需体积。
沉淀蛋白质的通用方法(TCA,乙醇,丙酮沉淀蛋白操作技巧步骤)
沉淀蛋白质的常用方法(TCA、乙醇、丙酮沉淀蛋白操作步骤)TCA-DOCFor precipitation of very low protein concentration1) To one volume of protein solution, add 1/100 vol. of 2% DOC (Na deoxycholate, detergent).2) Vortex and let sit for 30min at 4oC.3) Add 1/10 of Trichloroacetic acid (TCA) 100% vortex and let sit ON at 4oC (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see). [OPTION: Wash pellet twice with one volume of cold acetone (acetone keep at –20oC). Vortex and repellet samples 5min at full speed between washes].5) Dry samples under vaccum (speed vac) or dry air. For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of theacidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Normal TCATo eliminate TCA soluble interferences and protein concentration1) To a sample of protein solution add Trichloroacetic acid (TCA) 100% to get 13% final concentration. Mix and keep 5min –20oC and then 15min 4oC; or longer time at 4oC without the –20oC step for lower protein concentration. Suggestion: leave ON if the protein concentration is very low.(preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) For PAGE-SDS, resuspend samples in a minimal volume of sample buffer. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1NNaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Acetone PrecipitationTo eliminate acetone soluble interferences and protein concentration 1) Add to 1 volume of protein solution 4 volumes of cold acetone. Mix and keep at least 20min –20oC. (Suggestion: leave ON if the protein concentration is very low).2) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Add to 1 volume of protein solution 9 volumes of cold Ethanol 100%. Mix and keep at least 10min.at –20oC. (Suggestion: leave ON).2) Spin 15min 4oC in microcentrifuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).3) Wash pellet with 90% cold ethanol (keep at –20oC). Vortex and repellet samples 5min at full speed.4) Dry samples under vaccum (speed vac) or dry air to eliminate any ethanol residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.TCA-DOC/AcetoneUseful method to concentrate proteins and remove acetone and TCA soluble interferences1. To one volume of protein solution add 2% Na deoxycholate (DOC) to 0.02% final (for 100 μl sample, add 1 μl 2% DOC).2. Mix and keep at room temperature for at least 15 min.3. 100% trichloroacetic acid (TCA) to get 10% final concentration(preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).4. Mix and keep at room temperature for at least 1 hour.5. Spin at 4oC for 10 min, remove supernatant and retain the pellet. Dry tube by inversion on tissue paper.6. Add 200 μl of ice cold acetone to TCA pellet.7. Mix and keep on ice for at least 15 min.8. Spin at 4oC for 10 min in microcentrifuge at maximum speed.9. Remove supernatant as before (5), dry air pellet to eliminate any acetone residue (smell tubes). For PAGE-SDS, resuspend samples in a minimal volume of sample buffer.10. (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)Acidified Acetone/MethanolUseful method to remove acetone and methanol soluble interferences like SDS before IEF1) Prepare acidified acetone: 120ml acetone + 10μl HCl (1mM final concentration).2) Prepare precipitation reagent: Mix equal volumes of acidified acetone and methanol and keep at -20oC.3) To one volume of protein solution add 4 volumes of cold precipitation reagent. Mix and keep ON at -20oC.4) Spin 15min 4oC in microfuge at maximum speed (15000g). Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue paper (pellet may be difficult to see).5) Dry samples under vaccum (speed-vac) or dry air to eliminate any acetone or methanol residue (smell tubes).TCA-Ethanol PrecipitationUseful method to concentrate proteins and removal of Guanidine Hydrochloride before PAGE-SDS1) Dilute 10-25μl samples to 100μl with H2OAdd 100μl of 20% trichloroacetic acid (TCA) and mix (preparation of 100% TCA: 454ml H2O/kg TCA. Maintain in dark bottleat 4oC.Be careful, use gloves).2) Leave in ice for 20min. Spin at 4oC for 15 min in microcentrifuge at maximum speed.3) Carefully discharge supernatant and retain the pellet: dry tube by inversion on tissue (pellet may be difficult to see).4) Wash pellet with 100μl ice-cold ethanol, dry and resuspend in sample buffer.5) In case there are traces of GuHCl present, samples should be loaded immediately after boiling for 7 min at 95°C6) (The presence of some TCA can give a yellow colour as a consequence of the acidification of the sample buffer ; titrate with 1N NaOH or 1M TrisHCl pH8.5 to obtain the normal blue sample buffer colour.)PAGE prep TM Protein Clean-up and Enrichment Kit - PIERCEThe PAGEprep? Kit enables removal of many chemicals that interfere with SDS-PAGE analysis: guanidine, ammonium sulfate, other common salts, acids and bases, detergents, dyes, DNA, RNA, and lipids.PIERCE: #26800 - PAGE prep TM Protein Clean-up and EnrichmentKit (pdf)Chloroform Methanol PrecipitationUseful method for Removal of salt and detergents1) To sample of starting volume 100 ul2) Add 400 ul methanol3) Vortex well4) Add 100 ul chloroform5) Vortex6) Add 300 ul H2O7) Vortex8) Spin 1 minute @ 14,0000 g9) Remove top aqueous layer (protein is between layers)10) Add 400 ul methanol11) Vortex12) Spin 2 minutes @ 14,000 g13) Remove as much MeOH as possible without disturbing pellet14) Speed-Vac to dryness15) Bring up in 2X sample buffer for PAGEReference: Wessel, D. and Flugge, U. I. Anal. Biochem. (1984) 138, 141-143蛋白质浓缩——方法很全1130徐炉李2011-05-28 14:35楼主蛋白质浓缩——方法很全- 丁香园论坛-医学/药学/生命科学论坛蛋白质浓缩方法总结一个简便的方法你可以试试:找一透析袋,底部扎紧,袋口扎一去底的塑料或玻璃试管,将待浓缩的液体从管口灌入透析袋中,将整个装置挂在冰箱中,或者用电风扇吹,液体干后可再继续加入,直至样品浓缩至所需体积。
TCA-丙酮沉淀法浓缩蛋白
TCA-丙酮沉淀法浓缩蛋白TCA-丙酮蛋白浓缩TCA protein precipitation protocolStock Solutions: 100% (w/v) Trichloroacetic acid (TCA)recipe: dissolve 500g TCA (as shipped) into 350 ml dH2O, store at RT.Precipitation Protocol:1. Add 1 volume of TCA stock to 4 volumes of protein sample.i.e. in 1.5ml tube with maximum vol., add 250μl TCA to 1.0ml sample.2. Incubate 10 min at 4°C.3. Spin tube in microcentrifuge at 14K rpm, 5 min.4. Remove supernatant, leaving protein pellet intact. Pellet should be formed from whitish,fluffy ppt.5. Wash pellet with 200μl cold acetone.6. Spin tune in microfuge at 14K rpm, 5min.7. Repeat steps 4-6 for a total of 2 acetone washes.8. Dry pellet by placing tube in 95°C he at block for 5-10 min to drive off acetone.9. For SDS-PAGE, add 2X or 4X sample buffer (with or without bME) and boil smaple for10 min in 95°C herat block before loading smaple onto polyacrylamide gel.TCA蛋白浓缩步骤:储存液:100%(W/V)三氯乙酸(TCA)配制:将500g TCA溶解到350ml dH2O中,室温储存。
蛋白质提取方法比较
蛋白质定量
1.采用Bradford方法测定蛋白质的含量。 2.将待测蛋白的OD值,与标准蛋白绘制的标准曲线比对,根 据标准曲线查得待分析蛋白提取液中蛋白质的浓度。
电泳析
1.取少量琼脂糖封胶液封底; 2.随后加入聚丙烯酰胺凝胶( 分离胶),插入梳子,继续添加浓 缩胶,待胶体凝固后拔出梳子; 3.每一点样孔中点样 ; 4.以冰醋酸溶液作为电解液,电泳仪设定为恒流25 mA,电 泳100 min 左右。
1.参照苏源等人的方法提取总蛋白。 2.分别取处理和对照植物各2 g 利用液氮,研磨, 将其悬浮于TCA/丙酮溶液, -20℃过夜沉淀。 3.次日混均匀后,15 000 r/min、4℃离心20 min, 弃上 清重复上述操作,直至试管中无绿色为止。 4.在-20℃静置15min, 15000 r/min、4℃条件下离 15min弃上清液,将试管中的沉淀用手指弹出离心 管,以便丙酮挥发,在自然条件下吹干成粉末即 得到粗蛋白。
(二). Tris-HCl 缓冲液
1.参照谷瑞升等人的方法。 2.选取新鲜植物0.3 g。 3.加入少许石英砂和0聚乙烯吡咯烷酮(PVPP)置于预冷的研 钵中,用液氮迅速将其研磨成粉末状,移入离心管中, Tris-HCl缓冲液,涡旋混匀提取。 4.12 000 r/pm、4℃离心15 min,去除组织及细胞碎片。 5.取上清,作为粗样品-70℃保存备用。
胶体染色
1.凝胶染色采用胶体考马斯亮蓝染色法; 2.首先将凝胶至于蒸馏水中漂洗三次,每次不得超过1秒,然 后至于固定液(40%甲醇,10%冰乙酸)中染色30min; 3.然后至于胶体考马斯亮蓝染色液(0.12% 考马斯亮蓝 G-250, 10% 硫酸铵,10%磷酸,20%甲醇)中染色; 4.过夜,期间要将凝胶及其染色液放在摇床上轻轻摇荡; 5.第二日用蒸馏水清洗到蛋白质点清晰可见为止,记录并照 相留底。
蛋白浓度的方法
蛋白浓缩的方法
(因为百度文库下载要积分,所以把自己在生物论坛写的帖子上传换点积分)
常规方法有:丙酮沉淀法,TCA沉淀法,还有浓缩柱浓缩法,柱浓缩法用到浓缩柱,可能有点小贵,但是效果很好。
下面介绍下具体过程:
丙酮沉淀法,TCA沉淀法见《蛋白技术手册》P60,提供一个直接有的群共享:HelixNet4群毕赤酵母 53074791 在群共享里有,
在此不写了。
浓缩柱浓缩+TCA法【本人原创、供大家参考】
1、取诱导表达菌液1ml
2、离心取上清400ul加到浓缩柱中,离心至剩余约100ul
3、将100ul剩余液体加入10ulTCA【过程参考《蛋白技术手册》P60,本人做了一些改进】
4、冰上放置20-30min
5、离心,弃上清,洗涤后,37度烘干
6、加入10ulPBS溶解,再加10ulbuffer,沸水5min
7、上样,其余都一样。
补充:浓缩柱:Ultracel YM-10 1包¥450。
【我的蛋白大概20KD,所以选用了10KD的柱子】
部分问题汇总:
Q: 我就用TCA 浓缩的,浓缩50倍也没有看见条带,准备放弃了
A:有的时候不见得是没有表达,有可能是表达量低检测不到
Q: 柱浓缩在哪个公司买的,之前用透析袋浓缩过,效果都不好
A: Ultracel YM-10 1包¥450 分子公用
Q: Ultracel YM-10、YM-30 配合用来超滤上清获得20KD是不是更好啊?
A:建议用分子量小的,比如分子量20KD,有可能有糖基化,或者几聚体什么的超过30KD
Q:我的蛋白17KD可以用多大的
A:10KD甚至更小。
真菌蛋白提取方法
真菌蛋白提取方法一TCA/丙酮法1 液氮将菌体研磨为粉末;2 向匀浆中加入10倍体积的丙酮(含13.3% (w/v) TCA和0.093% β巯基乙醇),过夜沉降;3 4 度20,000g 离心15 min;4 移处上清,用冰冷的含0.07% (v/v) β-巯基乙醇的丙酮清洗沉淀两次;5 离心后,沉淀干燥至丙酮挥发完全。
二酚抽提法1 在液氮中将 1g 菌体研磨为粉末2 加入 6 ml 水饱和酚(buffer-saturated phenol)和 2 ml提取液(20mMTris-Cl, pH 7.5, 0.5% Triton X-100 (v/v), 0.5M EDTA, pH 7.5, pH 8.0,0.07% β-巯基乙醇, protease inhibitors)。
3 在4度混合30分钟。
4 12000 rmp 离心1min,使两相分开。
5 弃沉淀,吸取上层的苯酚相,加入5倍体积的冷丙酮,-20度沉降2h。
6 12000 rmp,4度,离心15分钟沉淀蛋白,弃去上清。
7 沉淀干燥至丙酮挥发完全。
三提取液抽提丙酮沉淀法1 预先将研钵置于-20℃的冰箱内冷冻。
2 取液氮冻存的菌体,放入预冷的研钵内研磨至粉末状。
3 向匀浆中加入2倍体积的抽提液(20mM Tris-Cl, pH 7.5, 0.5% Triton X-100(v/v), 0.5M EDTA, pH 7.5, pH 8.0, 0.07% β-巯基乙醇, protease inhibitors)。
4 混匀后4度震荡30分钟,以便蛋白溶解。
5 12000 rmp,4度,离心15分钟,吸取上清于另一EP管中。
7 向上清液中加入5倍体积的预冷丙酮(含有0.07%β-巯基乙醇),混匀,-20℃,2小时沉淀蛋白质。
8 12000 rmp,4度,离心15分钟沉淀蛋白。
弃去上清,沉淀用乙醇洗三次,自然干燥蛋白沉淀。
四甲醇氯仿水沉淀法Chloroform /Methanol/Water Precipitation1 预先将研钵置于-20℃的冰箱内冷冻。
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TCA-丙酮蛋白浓缩
TCA protein precipitation protocol
Stock Solutions: 100% (w/v) Trichloroacetic acid (TCA)
recipe: dissolve 500g TCA (as shipped) into 350 ml dH2O, store at RT.
Precipitation Protocol:
1. Add 1 volume of TCA stock to 4 volumes of protein sample.
i.e. in 1.5ml tube with maximum vol., add 250µl TCA to 1.0ml sample.
2. Incubate 10 min at 4°C.
3. Spin tube in microcentrifuge at 14K rpm, 5 min.
4. Remove supernatant, leaving protein pellet intact. Pellet should be formed from whitish,fluffy ppt.
5. Wash pellet with 200µl cold acetone.
6. Spin tune in microfuge at 14K rpm, 5min.
7. Repeat steps 4-6 for a total of 2 acetone washes.
8. Dry pellet by placing tube in 95°C heat block for 5-10 min to drive off acetone.
9. For SDS-PAGE, add 2X or 4X sample buffer (with or without bME) and boil smaple for
10 min in 95°C herat block before loading smaple onto polyacrylamide gel.
TCA蛋白浓缩步骤:
储存液:100%(W/V)三氯乙酸(TCA)
配制:将500g TCA溶解到350ml dH2O中,室温储存。
浓缩步骤:
1.加1倍体积的TCA储存液到4倍体积的蛋白样品中。
如:在1.5ml的离心管中,1ml
样品中加入250ul的TCA。
2.4度孵育10min。
3.14 000rpm 离心5 min。
4.弃上清
5.加入200ul预冷的丙酮洗涤沉淀。
6.14 000rpm 离心5 min。
7.重复步骤4-6两次。
8.95度5-10 min,晾干沉淀以彻底出去丙酮。
9.加入2X或4X样品buffer,煮沸样品10 min,SDS-PAGE
改进版:
TCA蛋白浓缩步骤:
储存液:100%(W/V)三氯乙酸(TCA)
配制:将500g TCA溶解到350ml dH2O中,室温储存。
浓缩步骤:
10.TCA储存液加到样品蛋白中,终浓度为10%,TCA缓慢滴入蛋白样品中;蛋白样品不
易过多,2ml左右即可,使用10ml离心管。
11.冰浴30-60min,时间久一点。
12.14 000rpm 离心5 min。
13.弃上清
14.加入400ul预冷的丙酮洗涤沉淀,(丙酮事先放入-30℃冰箱内冷冻至少半个小时以上)。
15.14 000rpm 离心5 min。
16.重复步骤4-6两次。
17.室温晾干沉淀,不易过干10-15min。
18.加入水溶解,若有结块或不溶可用8M尿素溶解;
19.区样品做跑胶样品处理,跑SDS胶。