jacs1989-1452(化学诺奖Corey文献集)
书写墨迹中9种染料的检测 液相色谱-高分辨质谱法
目次前言 (II)1 范围 (1)2 规范性引用文件 (1)3 术语和定义 (1)4 原理 (1)5 试剂、材料和仪器 (1)6 检测步骤 (2)7 结果评价 (3)8 方法检出限 (3)附录 A(资料性附录)9 种染料的液相色谱-高分辨质谱分析参数 (4)表 1 梯度洗脱程序 (3)前言本技术规范按照 GB/T 1.1-2009 给出的规则起草。
本技术规范由司法鉴定科学研究院提出。
本技术规范由司法部公共法律服务管理局归口。
本技术规范起草单位:司法鉴定科学研究院。
本技术规范主要起草人:孙其然、张清华、罗仪文、王雅晨、杨旭、施少培、卞新伟、奚建华。
本技术规范附录A为资料性附录。
本技术规范为首次发布。
书写墨迹中9种染料的检测液相色谱-高分辨质谱法1 范围本技术规范规定了应用液相色谱-高分辨质谱法检测书写墨迹中9种染料的试剂、材料、仪器、检测步骤、结果评价和方法检出限。
9种染料为:结晶紫、甲基紫2B、碱性蓝7、维多利亚蓝B、维多利亚蓝R、乙基紫、酸性蓝1、酸性蓝9和酸性红52。
本技术规范适用于以染料为着色剂的蓝色和黑色圆珠笔、中性笔、水笔书写形成的墨迹中上述9种染料的定性分析,以及墨迹中染料成分的比对检验。
2 规范性引用文件下列文件对于本文件的应用是必不可少的。
凡是注日期的引用文件,仅注日期的版本适用于本文件。
凡是不注日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。
GB/T 6682 分析实验室用水规格和试验方法SF/Z JD0201008-2010 文件材料鉴定规范GA/T 242 微量物证的理化检验术语3 术语和定义SF/Z 0201008-2010和GA/T 242中界定的术语和定义适用于本文件。
4 原理结晶紫、甲基紫2B、碱性蓝7、维多利亚蓝B、维多利亚蓝R、乙基紫、酸性蓝1、酸性蓝9和酸性红52是蓝色和黑色书写墨水中的常用染料。
墨迹中的染料经甲醇等溶剂提取后可用液相色谱-高分辨质谱仪进行检测。
德国1
APPLIED GENETICS AND MOLECULAR BIOTECHNOLOGY Corynebacterium glutamicum tailored for high-yield L-valine productionBastian Blombach&Mark E.Schreiner&Tobias Bartek&Marco Oldiges&Bernhard J.EikmannsReceived:31January2008/Revised:29February2008/Accepted:2March2008/Published online:1April2008 #Springer-Verlag2008Abstract We recently engineered the wild type ofCorynebacterium glutamicum for the growth-decoupledproduction of L-valine from glucose by inactivation of thepyruvate dehydrogenase complex and additional over-expression of the ilvBNCE genes,encoding the L-valinebiosynthetic enzymes acetohydroxyacid synthase,isomer-oreductase,and transaminase B.Based on the firstgeneration of pyruvate-dehydrogenase-complex-deficientC.glutamicum strains,a second generation of high-yield L-valine producers was constructed by successive deletion of the genes encoding pyruvate:quinone oxidoreductase,phosphoglucose isomerase,and pyruvate carboxylase andoverexpression of ilvBNCE.In fed-batch fermentations athigh cell densities,the newly constructed strains producedup to410mM(48g/l)L-valine,showed a maximum yieldof0.75to0.86mol/mol(0.49to0.56g/g)of glucose in theproduction phase and,in contrast to the first generationstrains,excreted neither pyruvate nor any other by-producttested.Keywords Corynebacterium glutamicum.L-valine production.Pyruvate dehydrogenase complex. Pyruvate:quinone oxidoreductase.Phosphoglucose isomerase.Pyruvate carboxylase IntroductionCorynebacterium glutamicum is a Gram-positive soil bacterium that grows on a variety of sugars and organic acids.The organism is the workhorse for the production of the amino acids L-glutamate and L-lysine(Liebl1991; Leuchtenberger et al.2005;Takors et al.2007).Further-more,a few thousand tons per year of other amino acids like L-threonine,L-isoleucine,L-tryptophan,and also L-valine are produced with C.glutamicum(Eggeling and Bott 2005).The latter branched-chain amino acid is essential for vertebrates and used for infusion solutions,for cosmetics, and as a precursor for the chemical synthesis of some herbicides(Leuchtenberger1996;Eggeling2001;Park et al.2007).Because the yields and the productivities of amino acid production strains still are below the expected theoretical values,there is a large interest to further improve the performance of bacterial production strains(Takors et al.2007).As shown in Fig.1,L-valine is synthesized from py-ruvate in a pathway comprising four reactions,catalyzed by acetohydroxyacid synthase(AHAS,ilvBN gene product), acetohydroxyacid isomeroreductase(AHAIR,the ilvC gene product),dihydroxyacid dehydratase(DHAD,ilvD gene product),and transaminase B(TA,ilvE gene product; Marienhagen et al.2005)(for an overview see Patek2007). The same four enzymes catalyze also the biosynthesis ofAppl Microbiol Biotechnol(2008)79:471–479DOI10.1007/s00253-008-1444-zB.Blombach:M.E.Schreiner:B.J.Eikmanns(*) Institute of Microbiology and Biotechnology,University of Ulm,89069Ulm,Germanye-mail:bernhard.eikmanns@uni-ulm.deT.Bartek:M.OldigesInstitute of Biotechnology2,Research Center Jülich, 52425Jülich,GermanyPresent address:M.E.SchreinerR&D Women’s Health,Europe,Johnson&Johnson GmbH, 42289Wuppertal,GermanyL -isoleucinefrom pyruvate and 2-oxobutyrate.The latterenzyme is formed from L -threonine by the threonine dehydratase (TD,ilvA gene product).Ketoisovalerate,the last intermediate of L -valine synthesis,is also the precursor for L -leucine and D -pantothenate biosynthesis.In C .glutamicum strains lacking TD,it has been shown that plasmid-bound overexpression of the genes ilvBNCD or ilvBNCE was beneficial for L -valine production (Sahm and Eggeling 1999;Radmacher et al.2002).Introduction of the genes encoding a feedback-resistant AHAS enzyme into L -valine-producing C .glutamicum strains led to further improvement of L -valine production (Elisakova et al.2005).Moreover,Radmacher et al.(2002)showed that inactivation of D -pantothenate biosynthesis by deleting the panBC genes led to an increased L -valine production of C .glutamicum when cultivated under D -pantothenate-limiting conditions.This latter improvement of L -valine production probably can be explained by an increased precursor (pyruvate)availability (Bartek et al.2008b )because D -pantothenate limitation leads to reduced coenzyme A availability for the reaction of the pyruvate dehydrogenase complex (PDHC).The importance of precursor availability was also high-lighted for L -lysine production by increasing the pyruvate and/or oxaloacetate supply either by inactivation of the PDHC complex (Blombach et al.2007a ),overexpression of the pyruvate carboxylase (PCx)gene (Peters-Wendischet al.2001),or inactivation of the phosphoenolpyruvate carboxykinase gene (Riedel et al.2001).Aside from engineering the biosynthetic pathways and increasing the precursor availability,NADPH supply was also shown to be a critical factor for amino acid production,as has been in detail studied in the case of L -lysine accumulation with C .glutamicum (Marx et al.2003;Kabus et al.2007).C .glutamicum possess four enzymes for NADPH gener-ation,notably,glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase of the oxidative pentose phosphate pathway (Moritz et al.2000),malic enzyme (Gourdon et al.2000),and isocitrate dehydrogenase (Eikmanns et al.1995).However,carbon flux analysis in a L -lysine-producing C .glutamicum strain revealed that in minimal medium with glucose the latter two enzymes play a minor role for the generation of NADPH (Marx et al.1996,1997,1999,2003).Increased flux from glycolysis to the pentose phosphate pathway and,thus,an increased NADPH supply was achieved by introduction of a mutant allele encoding a feedback-resistant 6-phosphogluconate dehydro-genase (Ohnishi et al.2005)and also by overexpression of fructose 1,6-biphosphatase (Georgi et al.2005;Becker et al.2005).Furthermore,Marx et al.(2003)reported that the disruption of the phosphoglucose isomerase (PGI)redirected the carbon flux towards the pentose phosphate pathwayGlucose Pentose-PFig.1Schematic representation of the central metabolism of C .glutamicum with the biosyn-thetic pathway of L -valine.Abbreviations:AHAIR ,acetohy-droxyacid isomeroreductase;AHAS ,acetohydroxyacid synthase;AK ,acetate kinase;DHAD ,dihydroxyacid dehydra-tase;PCx ,pyruvate carboxylase;PDHC ,pyruvate dehydrogenase complex;PK ,pyruvate kinase;PEP ,phosphoenolpyruvate;PEPCk ,PEP carboxykinase;PEPCx ,PEP carboxylase;PGI ,phosphoglucose isomerase;PQO ,pyruvate:quinone oxidoreductase;PTA ,phosphotransacetylase;TA ,transaminase Bresulting in increased L-lysine formation.In contrast to L-lysine synthesis,which requires4mol NADPH per molof L-lysine,for the generation of1mol L-valine only2mol of NADPH are oxidized,one for the conversion of acetolactate by the AHAIR,the other for the synthesis of the primary amino group donor glutamate(Fig.1).However, based on a correlation between the cell-specific rate of L-valine production and the specific activity of the glucose-6-phosphate dehydrogenase at different growth rates of a TD-deficient C.glutamicum strain,Ruklisha et al.(2007) suggested that an increase in NADPH generation might be advantageous for L-valine production.We recently demonstrated the ability of PDHC-deficient C. glutamicum strains to form L-valine,L-alanine,and pyruvate from glucose.Additional plasmid-bound overexpression of the L-valine biosynthesis genes ilvBNCE shifted the product spectrum towards L-valine and resulted in an L-valine producer,excreting this amino acid in a growth-decoupled manner(Blombach et al.2007b).In contrast to the previously constructed L-valine producer C.glutamicum ΔilvAΔpanBC(pJC4ilvBNCD)(Radmacher et al.2002;see above),the PDHC-deficient strains do not require supple-ments such as L-isoleucine and D-pantothenate.This fact and the further complication that L-valine was shown to inhibit L-isoleucine uptake of C.glutamicumΔilvAΔpanBC (pJC4ilvBNCD)(Lange et al.2003)suggest that PDHC-deficient C.glutamicum strains are more favorable L-valine producers.Based on the first generation of PDHC-deficient L-valine producers,we here highlight the importance of the enzymes AHAS,AHAIR,and TA for L-valine overproduc-tion by testing the effect of different combinations of plasmid-bound L-valine biosynthetic genes.Furthermore, we investigate the importance of an increased precursor supply by further inactivation of pyruvate-converting enzymes.Finally,we test whether an increase of the NADPH supply,brought about by forcing the carbon flux through the pentose phosphate pathway,is beneficial for L-valine production with C.glutamicum.Materials and methodsBacterial strains,plasmids,and oligonucleotidesAll bacterial strains and plasmids and their relevant characteristics and sources are given in Table1.The oligonucleotides used and their sequences are also listed in Table1.DNA preparation and transformationThe isolation of plasmids from Escherichia coli and C. glutamicum was performed as described before(Eikmanns et al.1994).Plasmid DNA transfer into C.glutamicum was carried out by electroporation and the recombinant strains were selected on Luria–Bertani Brain Heart Infusion (BHI)agar plates containing0.5M sorbitol,85mM potassium acetate(corresponds to0.5%(w/v)acetate), and kanamycin(50μg ml−1;van der Rest et al.1999).The isolation of chromosomal DNA from C.glutamicum was performed as described previously(Eikmanns et al.1994). Electroporation of E.coli was performed with competent cells according to the method of Dower et al.(1988).Construction of C.glutamicumΔaceEΔpqoΔpgi and C. glutamicumΔaceEΔpqoΔpgiΔpycInactivation of the chromosomal PGI gene(pgi)in C. glutamicumΔaceEΔpqo(Schreiner et al.2006)was performed using crossover PCR and the suicide vector pK18mobsacB.DNA fragments covering the5′-end and the3′-end of pgi were generated using the primer pairs pgi-d1–pgi-d2and pgi-d3–pgi-d4,respectively.The two fragments were purified,mixed in equal amounts,and subjected to crossover PCR using primers pgi-d1and pgi-d4.The resulting fusion product(containing the pgi gene with an internal deletion of1,504bp)was ligated into SmaI-restricted plasmid pK18mobsacB and trans-formed into E.coli.The recombinant plasmid was isolated from E.coli and electroporated into C.glutamicumΔaceE Δpqo.By application of the method described by Schäfer et al.(1994),the intact chromosomal pgi gene in C. glutamicumΔaceEΔpqo was replaced by the truncated pgi gene via homologous recombination(double cross-over).The screening of the pgi mutants was done on 2xTY agar plates(Sambrook et al.2001)containing 85mM potassium acetate(corresponds to0.5%(w/v) acetate)and10%(w/v)sucrose.The replacement at the chromosomal locus was verified by PCR using primers pgiout1–pgiout2.Inactivation of the chromosomal PCx gene(pyc)in C. glutamicumΔaceEΔpqoΔpgi was performed as described previously for C.glutamicumΔpyc(Peters-Wendisch et al. 1998),using the suicide vector pK19mobsacBΔpyc.The deletion at the chromosomal locus was verified by PCR using primers pycfow1–pycrev1.Culture conditions and fermentationsE.coli was grown aerobically in2xTY complex medium at 37°C as50-ml cultures in500-ml baffled Erlenmeyer flasks on a rotary shaker at120rpm.Precultures of the different C.glutamicum strains were grown in2xTY medium containing28mM glucose(corresponds to0.5%(w/v) glucose)and85mM potassium acetate.The plasmid-carrying strains were grown in the presence of kanamycin(50μg ml−1).Culture conditions for shake-flask amino acid fermentations and fed-batch fermentations in an1-l glass bioreactor(Biostat B;Braun,Melsungen,Germany)were performed as described before(Blombach et al.2007b).AnalyticsFor quantification of substrate consumption and product formation,1-ml samples were taken from the cultures and centrifuged at13,000rpm(10min)and the super-natant was used for determination of amino acids, glucose,and/or organic acid concentrations in the culture fluid.The amino acid concentrations were determined by reversed-phase high-pressure liquid chromatography as described before(Blombach et al.2007b).Glucose, acetate,and lactate concentrations were determined by enzymatic tests from Roche Diagnostics.The pyruvate concentrations were determined enzymatically according to Bergmeyer(1983).ResultsL-Valine production by C.glutamicumΔaceE strains overexpressing different ilv genesPreviously,we demonstrated the ability of C.glutamicum ΔaceE to form pyruvate,L-alanine,and L-valine.Plasmid-bound overexpression of the ilvBNCE genes in C. glutamicumΔaceE directed the carbon flux from pyruvate and L-alanine to L-valine(Blombach et al.2007b).To study the relevance of ilvD as compared to ilvE overexpression on L-valine production,plasmids pJC4ilvBNC,pJC4ilvBNCD, and pJC4ilvBNCE were transformed into C.glutamicumTable1Strains,plasmids,and oligonucleotides used in this studyStrain,plasmid,oroligonucleotideRelevant characteristic(s)or sequence Source–reference or purposeStrainsE.coli DH5αsupE44hsdR17recA1endA1gyrA96thi-1relA1Hanahan1985C.glutamicumΔaceE C.glutamicum wild type(ATCC13032)with deletion of the E1pgene(aceE)of the PDHCSchreiner et al.2005C.glutamicumΔaceE Δpqo ΔaceE strain with deletion of the pyruvate:quinone oxidoreductasegene pqoSchreiner et al.2006C.glutamicumΔaceE ΔpqoΔpgi ΔaceEΔpqo strain with deletion of the phosphoglucose isomerasegene pgiThis workC.glutamicumΔaceE ΔpqoΔpgiΔpyc ΔaceEΔpqoΔpgi strain with deletion of the pyruvate carboxylasegene pycThis workPlasmidspK18mobsacB Km r,mobilizable(oriT),oriV Schäfer et al.1994pK18mobsacB pgidel pK18mobsacB carrying a truncated pgi gene(shortened by1,504bp)This workpK19mobsacBΔpyc pK19mobsacB carrying a truncated pyc gene(shortened by2,421bp)Peters-Wendisch et al.1998 pJC4ilvBNC Plasmid carrying the ilvBNC genes encoding the L-valine biosyntheticenzymes acetohydroxyacid synthase and isomeroreductaseSahm et al.1999pJC4ilvBNCD Plasmid carrying the ilvBNCD genes encoding the L-valine biosyntheticenzymes acetohydroxyacid synthase,isomeroreductase anddihydroxyacid dehydrataseSahm et al.1999pJC4ilvBNCE Plasmid carrying the ilvBNCE genes encoding the L-valine biosyntheticenzymes acetohydroxyacid synthase,isomeroreductase andtransaminase BRadmacher et al.2002Oligonucleotidespgi-d15′-ACGACCTCACCTACGGCGAA-3′Primer for deletion of pgipgi-d25′-TGGGGTCCAAATGTCCCTGGGTGGTCGAAATGTCC-3′Primer for deletion of pgi,crossover overlap underlined pgi-d35′-GGACATTTCGACCCCAAATGACCTCGCTCCGG CT-3′Primer for deletion of pgi,crossover overlap underlined pgi-d45′-CCCCACACCAACCGAAGACT-3′Primer for deletion of pgi pgiout15′-GGAACGACACCAGATAAG-3′Primer to verify pgi deletion pgiout25′-CACTCATTGGTCGTGATG-3′Primer to verify pgi deletion pycfow15′-GCAGATGCCATTTACCCG-3′Primer to verify pyc deletion pycrev15′-CGGTGACAGACTCAACG-3′Primer to verify pyc deletionΔaceE and shake-flask fermentations with the resulting strains carried out in CGXII medium with 0.5%(w /v )BHI,4%(w /v )glucose,and 1%(w /v )acetate.All cultures grew within 8h to an OD 600of about 20,consuming acetate completely and glucose to a minor part (decrease from 4.0%to 3.5%).The cells then stopped growing;however,they further consumed glucose and accumulated L -valine (data not shown).After complete consumption of the glucose (i.e.,at t =72h),C .glutamicum ΔaceE (pJC4ilvBNC)and C .glutamicum ΔaceE (pJC4ilvBNCD)produced 67±15and 73±4mM L -valine,respectively,whereas overexpression of the ilvBNCE genes resulted in a significantly higher L -valine accumulation of 106±9mM L -valine.All three strains excreted additionally 20to 30mM pyruvate into the medium,indicating that there is still precursor available for further L -valine production.These results show that,aside from AHAS (ilvBN gene product)and AHAIR (ilvC gene product),the TA (ilvE gene product)might be a major bottleneck for efficient L -valine overproduction by C .glutamicum ΔaceE .Relevance of pyruvate:quinone oxidoreductase for L -valine production with C .glutamicum ΔaceEPreviously,we showed the suitability of C .glutamicum ΔaceE (pJC4ilvBNCE)for a L -valine production process by fed-batch fermentation (Blombach et al.2007b ).To study the relevance of the pyruvate:quinone oxidoreductase (PQO;pqo gene product)for L -valine accumulation,we transformed C .glutamicum ΔaceE Δpqo (Schreiner et al.2006)with plasmid pJC4ilvBNCE and performed comparative fed-batch fermentations with C .glutamicum ΔaceE (pJC4ilvBNCE)and C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE).These fermentations were carried out in CGXII medium initially containing about 4%(w /v )glucose,1.3%(w /v )acetate,and0.5%(w /v )BHI.To allow growth to a high cell density,adequate amounts of a 50%(w /v )acetate stock solution were repeatedly added to the growing cells (Fig.2a,b).Within 11h,C .glutamicum ΔaceE (pJC4ilvBNCE)grew in a first exponential growth phase to an OD 600of about 39.In a second growth phase (t =9h to t =28h),C .glutamicum ΔaceE (pJC4ilvBNCE)showed linear growth up to an OD 600of 54(Fig.2a).In contrast C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE)grew exponentially to an OD 600of 54within 11h and stopped to grow immediately after having consumed the last acetate pulse completely (Fig.2b).With depletion of acetate,both strains started to excrete L -valine.As shown in Fig.2a,C .glutamicum ΔaceE (pJC4ilvBNCE)accumulated about 195mM L -valine within 25h with a volumetric productivity of 7.9mmol l −1h −1and a substrate-specific product yield (Y P/S )in the production phase of 0.39mol L -valine per mol of glucose.C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE)accumulated about 225mM L -valine within 24h (Fig.2b).The volumetric productivity was 9.5mmol l −1h −1with a Y P/S in the production phase of 0.52mol L -valine per mol of glucose.In addition to L -valine,both strains also excreted small amounts of pyruvate (about 5mM)into the medium,indicating that L -valine production by both C .glutamicum ΔaceE (pJC4ilvBNCE)and C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE)can be further increased.Taken together,these results show that the absence of PQO in C .glutamicum ΔaceE (pJC4ilvBNCE)resulted in about 30%increased Y P/S in the production phase.Relevance of PGI for L -valine production with C .glutamicum ΔaceE ΔpqoTo investigate the relevance of PGI and,thus,the in-fluence of an increased NADPH supply for L -valine production,we constructed plasmid pK18mobsacBpgidel10203040Time [h]G r o w t h [O D 600] G l u c o s e [g /l ]A c e t a t e [g /l ]50100150200250P y r u v a t e [m M]010203040Time [h]G r o w t h [O D 600] G l u c o s e [g /l ]A c e t a t e [g /l ]50100150200250P y r u v a t e [m M ]abL -V a l i n e [m M ]L -V a l i n e [m M ]Fig.2L -valine accumulation during representative fed-batch fermen-tations of a C .glutamicum ΔaceE (pJC4ilvBNCE)and b C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE)in CGXII medium initially containing glucose,acetate and BHI.Empty diamond ,growth;filledsquare ,glucose;empty square ,acetate;empty triangle ,pyruvate;filled circle ,L-valine.Three independent fed-batch fermentations were performed;all three showing comparable resultsand inactivated the chromosomal PGI gene (pgi )in C .glutamicum ΔaceE Δpqo .First,we compared the growth of C .glutamicum ΔaceE Δpqo with that of C .glutamicum ΔaceE Δpqo Δpgi in minimal medium containing either glucose plus acetate or fructose plus acetate.In minimal medium containing 0.5%(w /v )glucose and 0.5%(w /v )acetate,C .glutamicum ΔaceE Δpqo grew with a growth rate of 0.35h −1to an OD 600of about 9after 24h.C .glutamicum ΔaceE Δpqo Δpgi grew to nearly the same final OD 600,however,showed a lower growth rate of 0.27h −1(data not shown).In minimal medium with 0.5%(w /v )fructose and 0.5%(w /v )acetate,C .glutamicum ΔaceE Δpqo grew with a slightly higher growth rate of 0.39h −1to an OD 600of about 9after 24h.In contrast,C .glutamicum ΔaceE Δpqo Δpgi showed only poor growth with a growth rate of 0.17h −1and a final OD 600of 4.5after 24h,indicating that PGI is essential for optimal growth of C .glutamicum ΔaceE Δpqo on fructose plus acetate.This phenotype was expected,as C .glutamicum possess no PGI isoenzyme (Marx et al.2003)for the formation of glucose-6-P during growth in minimal medium with fructose and acetate.For testing the relevance of PGI for L -valine production,C .glutamicum ΔaceE Δpqo Δpgi was transformed with plasmid pJC4ilvBNCE and fed-batch fermentations with the resulting strain were carried out in CGXII medium containing 0.5%(w /v )BHI,4.5%glucose,and an acetate concentration of 1.5%(w /v ).To allow growth to a high cell density,adequate amounts of a 50%(w /v )acetate stock solution were added twice to the growing cells (Fig.3).Using this technique,an OD 600of about 37was obtained after 15h (Fig.3).After having consumed the last pulse of acetate,the cells started to excrete L -valine and 15,29.5,and 49h after inoculation,we added glucose again to obtain concentrations of about 5%(w /v ).As shown in Fig.3,C .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE)accumulated about 412mM L -valine within 74h with a volumetric productivityof 5.6mmol l −1h −1and a Y P/S in the production phase of 0.75mol L -valine per mol of glucose.No pyruvate or any other of the tested byproducts were excreted into the medium.Relevance of PCx for L -valine production with C .glutamicum ΔaceE Δpqo ΔpgiThe observation that C .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE)did not secrete pyruvate into the culture broth suggested effective C-flux from pyruvate to aceto-lactate (and further to L -valine)and,thus,that in this strain the availability of pyruvate for L -valine production might become limiting.To test for this hypothesis and to possibly increase the pyruvate availability,we deleted the PCx gene (pyc )in C .glutamicum ΔaceE Δpqo Δpgi and trans-formed the resulting strain C .glutamicum ΔaceE Δpqo Δpgi Δpyc with plasmid pJC4ilvBNCE.For L -valine accumulation we carried out fed-batch fermentations in CGXII medium as described above for C .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE).After 18h,having consumed the second of two acetate pulses completely,C .glutamicum ΔaceE Δpqo Δpgi Δpyc (pJC4ilvBNCE)reached an OD 600of about 36and started to form L -valine from glucose.Within 46h,C .glutamicum ΔaceE Δpqo Δpgi Δpyc (pJC4ilvBNCE)then produced 240mM L -valine with a volumetric productivity of 5.2mmol l −1h −1and a Y P/S in the production phase of 0.86mol L -valine per mol (0.56g/g)of glucose.Neither acetate nor pyruvate was detectable in the growth medium.Comparison of L -valine accumulation and substrate-specific L -valine yieldsFigure 4summarizes L -valine accumulation and substrate-specific L -valine yields of the production phases of the C .glutamicum ΔaceE derivatives.C .glutamicum ΔaceE (pJC4ilvBNCE)accumulated about 200mM L -valinewith102030405060708090Time [h]G r o w t h [O D 600] G l u c o s e [g /l ]A c e t a t e [g /l ]50100150200250300350400450P y r u v a t e [m M ]L -V a l i n e [m M ]Fig.3L -valine accumulation during a representative fed-batch fermentation ofC .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE)in CGXII medium initially containing glucose,acetate,and BHI.Empty diamond ,growth;filled square ,glucose;empty square ,acetate;empty triangle ,pyruvate;filled circle ,L -valine.Two independent fed-batch fermentations were performed,both showing comparable resultsa Y P/S of 0.39mol L -valine per mol glucose in the production phase.PQO deficiency in this strain resulted in an about 13%higher L -valine accumulation and an about 30%increased Y P/S .Additional deletion of the PGI gene resulted in a drastic increase of L -valine accumulation (more than 400mM)and a Y P/S of 0.75mol L -valine per mol of glucose.Subsequent inactivation of the PCx in C .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE)resulted in the maximal theoretical Y P/S of 0.86mol L -valine per mol glucose however a lower accumulation of about 240mM L -valine (Fig.4).Taken together,these results show that pyruvate supply on the one hand,an increased NADPH availability on the other and,finally increasing the intra-cellular content of L -valine biosynthetic enzymes AHAS,AHAIR,and TA are highly beneficial for L -valine overpro-duction with C .glutamicum .DiscussionRadmacher et al.(2002)showed that overexpression of ilvBNC in combination with ilvD or ilvE in strains with deleted ilvA and/or panBC (see “Introduction ”)resulted in increased L -valine accumulation.Our findings here corrob-orate the importance of increasing the intracellular content of L -valine biosynthetic enzymes for L -valine production with C .glutamicum .Plasmid-bound expression of ilvBNC ,ilvBNCD ,or ilvBNCE shifted the product spectrum of C .glutamicum ΔaceE significantly from pyruvate and L -alanine towards L -valine.However,the fermentations with C .glutamicum ΔaceE harboring each of the three different plasmids revealed differences in L -valine accumulation and identified,aside from AHAS and AHAIR,the TA enzyme asmore important than DHAD for efficient L -valine production.This result is surprising because in C .glutamicum ΔilvA ΔpanBC the overexpression of ilvBNCD resulted in about 10%more L -valine than overexpression of ilvBNCE (91.9vs.81.2mM;Radmacher et al.2002).However,our results underline the importance of increasing TA activity for L -valine production with a PDHC-deficient C .glutamicum strain and based on these findings,C .glutamicum ΔaceE (pJC4ilvBNCE)represented the ideal platform for further strain improvement.Previously,Schreiner et al.(2006)observed no significant differences in growth of C .glutamicum ΔaceE and C .glutamicum ΔaceE Δpqo under several conditions in shake flasks.These results indicated that PQO is not relevant for growth of these strains under the given conditions.However,the authors also showed that overexpression of pqo in C .glutamicum ΔaceE resulted in linear growth in complex medium without acetate,indicating that PQO activity at least partially can compensate for PDHC activity in C .glutamicum (Schreiner et al.2006).We here show that C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE)stopped growing immediately after consumption of the last pulse of acetate whereas C .glutamicum ΔaceE (pJC4ilvBNCE)still showed linear growth after acetate was completely consumed.These results indicate that PQO and the acetate-activating enzymes acetate kinase and phosphotransacetylase can apparently catalyze the formation of acetyl-CoA to bypass the PDHC reaction and so contribute to growth of C .glutamicum ΔaceE (pJC4ilvBNCE)at high cell densities.Hence,inactivation of the PQO avoided withdrawal of pyruvate for growth purposes and resulted in an about 30%increased Y P/S .In fed-batch fermentations,both C .glutamicum ΔaceE (pJC4ilvBNCE)and C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE)still excreted pyruvate into the medium,indicating that L -valine production in these strains is limited by the reactions from pyruvate to L -valine.Stoichiometric network modeling and computational analysis of the central metabolism and of the L -valine biosynthetic pathway in C .glutamicum indicated that NADPH supply is critical for L -valine production from glucose (Bartek et al.2008a ).The modeling predicted an optimal NADPH supply and a maximal Y P/S of 0.86mol L -valine per mol of glucose when the carbon flux from glucose is completely directed into the pentose phosphate pathway instead of into glycolysis (Bartek et al.2008a ).In accordance,the fed-batch fermentations with C .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE)revealed a higher conversion of glucose to L -valine with a Y P/S of 0.75mol L -valine per mol of glucose when compared to the respective strain with intact PGI.Furthermore,the PGI-deficient strain produced up to 400mM L -valine and excreted no pyruvate into the medium.These results indicated that L -valine productionL -V a l i n e [m M ]50100150200250300350400450Y P /S [m o l /m o l]A B C DFig.4L -valine accumulation (black bars )and substrate-specific product yields (Y P/S in mol L-valine per mole glucose;grey bars )at the end of the production phases of representative fed-batch fermenta-tions of (A )C .glutamicum ΔaceE (pJC4ilvBNCE),(B )C .glutamicum ΔaceE Δpqo (pJC4ilvBNCE),(C )C .glutamicum ΔaceE Δpqo Δpgi (pJC4ilvBNCE),and (D )C.glutamicum ΔaceE Δpqo Δpgi Δpyc (pJC4ilvBNCE)in CGXII medium containing glucose,acetate,and BHI.Means are from at least two independent experiments。
英文天然产物化学文献查找
天然产物化学常用参考文献一、图书(一)天然产物化学一般理论1. 林启寿编著, 中草药成分化学, 科学出版社, 19772. 徐任生主编, 天然产物化学, 科学出版社, 19973. 姚新生主编. 天然药物化学(第三版). 人民卫生出版社, 20024. 杨其菖编. 天然药物化学,中国医药科技出版社, 19975. R. D. H. Murray. Progress in the Chemistry of Organic Natural Products. Springer Wien New York, 2002(二)成分提取分离1. 上海药物研究所编著. 中草药有效成分提取与分离. 上海科学技术出版社, 19832. Richard J. P. Cannell. Natural Products Isolation.Humana Press, 19983. Raphael Ikan. Natural Products -- A Laboratory Guide (Second Edition). Academic Press, 19914. J. B. Harborne. Phytochemical Methods -- A Guide to Modern Techniques of Plant Analysis (Three edition). Chapman & Hall, UK, 1998(三)化合物结构解析1. 梁晓天. 核磁共振. 科学出版社,19762. 洪山海. 光谱解析法在有机化学中的应用. 科学出版社, 19803. 赵天增. 核磁共振氢谱. 北京大学出版社, 19834. 沈其丰. 核磁共振碳谱. 北京大学出版社, 19885. 姚新生主编. 有机化合物波谱解析. 中国医药科技出版社, 20016. Dudley H. Willeams等著. 王剑波, 施卫峰译. 有机化学中的光谱方法. 北京大学出版社, 20017. 苏克曼, 潘铁英, 张玉兰. 波谱解析法. 华东理工大学出版社, 20028. E. Pretsch, P. Buhlmann, C. Affolter. 荣国斌译. 波谱数据表--有机化合物的结构解析. 华东理工大学出版社, 20029. 宁永成编著. 有机化合物结构鉴定与有机波谱学. 科学出版社, 199910. 于德泉, 杨峻山主编. 分析化学手册第七分册核磁共振波谱分析. 化学工业出版社, 199911. 丛浦珠. 质谱学在天然有机化学中的应用. 科学出版社, 198712. Biemann K. Tables of Spectral Data for Structure Determination of Organic Compounds (Second edition). Berlin; New York : Springer-Verlag, 198913. Crews, Phillip. Organic structure analysis. New York : Oxford University Press, 1998.14. Robert M. Silverstein and Francis X. Webster.Spectrometric identification of organic compounds. (6th ed.) New York : Wiley, 1998.15. Joseph B. Organic structural spectroscopy.Prentice Hall, 1998.16. Laurence M. H., Timothy D.W. Introduction to organic spectroscopy. New York : Oxford University Press, 1997.17. Meier, Bernd Zeeh. Spectroscopic methods in organic chemistry. New York : G. Thieme,1997.18. EberhardBreitmaier ; translated by Julia Wade. Structure elucidation by NMR in organic chemistry : a practical guide. New York : Wiley, 1993.19. Field L. D., Sternhell S., Kalman J.R. Organic structures from spectra. (2nd ed.) New York : John Wiley, 1995.20. ErnoPretsch. Spectra interpretation of organic compounds. New-York: Cambridge: VCH, 1997.21. Pretsch. [et al. translated from the German by K. Biemann]. Tables of spectral data for structure determination of organic compounds (2nd ed.) New York: Springer-Verlag, 1989.22. Robert V. Hoffman. Organic chemistry : an intermediate text. Oxford University Press, 1997.23. Gerhard Quinkert, Ernst Egert, Christian Griesinger. Aspects of organic chemistry : structure. Cambridge : VCH, 1996.(四)化合物查询1. 江纪武、肖庆祥编著. 植物药有效成分手册. 人民卫生出版社(1986年2. 中国科学院上海药物研究所植化室编译. 黄酮体化合物鉴定手册, 科学出版社(1981)3. 中国医学科学院药物研究所编著. 中草药有效成分的研究. 北京人民卫生出版, 19724. 黄天守编. 化学化工药学大辞典. 台北市大学图书公司出版, 19825. Dictionary of Natural Products on CD-ROM.(五)生物活性检测药理实验H. G. 沃格尔, W. H. 沃格尔编著.杜冠华, 李学军, 张永祥等译. 药理学实验指南——新药发现和药理学评价. 科学出版社, 2001(六)中药材1. 江苏新医学院编. 中药大辞典(上, 下册), 上海科学技术出版社, 20002. 全国中草药汇编编写组编. 全国中草药汇编(上, 下册), 人民卫生出版社, 19733. 刘寿山编著. 中药研究文献摘要(共四册). 科学出版社4. 中国科学院南海海洋研究所编著. 中国海洋药用生物. 科学出版社, 19785. 候宽昭编著. 中国种子植物科属词典. 科学出版社, 1982(七)其他王北婴、李仪奎编. 中药新药研制开发技术与方法. 上海科学技术出版社, 2001二、期刊1. Journal of Asian Natural Product Research, 中国医学科学院药物研究所主办2. 中国药理学报, 中国药学会主办3. 药学学报, 中国药学会主办4. 中国药学杂志, 中国药学会主办5. 中国中药杂志, 中国药学会主办6. 中草药, 中草药信息中心站、天津药物研究院主办7. 天然产物研究与开发, 中国科学院成都分院主办8. 国外医学植物药分册, 国家医药管理局中草药情报中心站(天津)主办9. 国外医学中医中药分册, 中国中医研究所情报研究室主办10. Phytochemistry11. PlantaMedica12. Journal of Natural Product13. Chemical & Pharmaceutical Bulletin14. Natural Product Letter15. Natural Product Peport16. Chemistry of Natural Compounds17. Journal of American Chemical Society18. Lipid19. Sterol三、检索工具1. 中文科技资料目录中草药2. 中国药学文摘3. Chemical Abstracts4. The Merck Index5.Dictionary of Organic Compounds6.CRC Handbook of Data Organic Compounds7.Index Chemicus8. The Sadtler Standard Spectra Total Spectra Indes。
jacs1994-12109(化学诺奖Corey文献集)
2
3
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4
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I
5
6
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10
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11
1.1 equiv of p-methoxybenzoyl chloride, 1.5 equiv of triethylamine, and 0.05 equiv of 4-(dimethy1amino)pyridine at 23 "C for 3 h. The p-methoxybenzoate 4 was chosen as a substrate for the critical chirality-producing step, Os04-biscinchona alkaloid catalyzed dihydroxylation, on the basis of the mechanistic model recently proposed to explain cases of high enantioselection.12 The mechanistic reasoning behind this choice is summarized below. Reaction of 4 with 1 mol % of KzOsO4, 1 mol % of the (DHQ)2PHAL biscinchona ligand (Aldrich Co.), 3 equiv of K3Fe(CN)6,3 equiv of K2CO3, and 1 equiv of CH3S02NH2 in a stirred two-phase mixture of t-BuOH-H2O at 0 "C for 4 h produced the dihydroxylation product 5 in 93% yield and '99% enantiomeric excess (ee).13 In sharp contrast, the corresponding reaction with the allylic alcohol 3 afforded the dihydroxylation product in only 18% ee and was, therefore, a totally unsuitable substrate. The asymmetric dihydroxylation of the pivalate and triisopropylsilyl derivatives of 3 proceeded with 35% and 13% ee, respectively. Oxidation of the secondary alcohol function in 5 (Swem method, oxalyl chloride, dimethyl sulfoxide, -78 "C for 30 min followed
有机化学全合成的艺术和科学
全合成的艺术和科学The Art and Science of Total Synthesis at the Dawn of the Twenty-First CenturyK. C. Nicolaou, Dionisios Vourloumis, Nicolas Winssinger, and Phil S. BaranDedicated to Professor E. J. Corey for his outstanding contributions to organic synthesisAngew. Chem. Int. Ed. 2000, 39, 44 -122有机合成从1828年尿素的合成开始。
尿素的合成具有划时代的意义,它打破了以往认为有机物是因为“原生命力”而产生的观点,打开了一个全新的天地。
从此人们开始人工合成大量的有机化合物。
十九世纪的全合成介绍:十九世纪的重要全合成有尿素,葡萄糖,乙酸,茜素,靛青。
尿素的意义已经介绍。
而这两个染料开创了德国一个神话般的染料工业时代。
葡萄糖的全合成由糖化学之父费歇尔完成,它的意义不仅仅在于产物的复杂性,而且在于其含氧的单环结构以及其五个手性中心,其中四个可控制。
众所周知,旋光异构在有机化学中很重要。
因为在糖类化学的杰出贡献,费歇尔获得第二个诺贝尔化学奖。
二战前的全合成介绍:文献提到,除了少数例子,十九世纪的全合成多半较简单,而且主要集中在芳香族化合物上,合成仅仅是进行了一些官能团化而已。
二战前的全合成开始涉及了一些很复杂的化合物和合成路线设计。
比较重要的有如下化合物:a-萜品醇,樟脑,托品酮,血红素,维生素B6,马萘雌酮(一种性激素)。
值得一提的是托品酮的合成。
基础有机里边介绍曼尼许反应的时候应该提到过这个物质,它的全合成是相当漂亮的,虽然反应分为多个步骤,粗略的看却可以认为是一步,高产率,原料简单(甲胺,丁二醛,酮二酸)。
而且多个片断一个反应连接起来的合成思想影响深远。
jacs1995-11819(化学诺奖Corey文献集)
UlJl
C(17) proton (a to C=O) appeared as a triplet at 2.87 6 (J = 8.5 Hz), indicating vicinal coupling to C(16)H2, but not to C( 13)H. In contrast, under the same conditions (S)-2,3oxidosqualene is converted cleanly to lanosterol by the yeast synthase with no sign of abnormal cyclization products comparable to 5.
J. Am. Chem. SOC.1995,117, 11819-11820
11819
New Insights Regarding the Cyclization Pathway for Sterol Biosynthesis from (S)-2,3-Oxidosqualene
E. J. Corey,* Scott C. Virgil, Hengmiao Cheng, C. Hunter Baker, Seiichi P. T. Matsuda, Vinod Singh, and Sepehr Sarhe formation of 5 is not readily rationalized on the basis of a mechanism which does not involve intermediate carbocations prior to generation of the 20-oxa analog of 2. On the other hand, if the cyclization of (S)-2,3-oxidosqualene proceeds via the discrete tricyclic cation 6 (the product of Markovnikov closure with respect to ring C), and if the resulting cyclopentylcarbinyl cation has a finite lifetime before ring expansion to form the tricyclic cyclohexyl carbocation 7 and further cyclization to the protosterol cation 2, the formation of the tetracyclic product 5 from 20-oxa-2,3-oxidosqualene (3) is simply explained as due to an enhanced trapping rate of carbocation 8 (before rearrangement to 9) because of the much greater nucleophilicity of the 18,19-double bond of 8 relative to 6. That is, in cation 8, the cyclization to the tetracyclic cation 11 is accelerated by the electron-donating 20-oxa function to the point where the normally very unfavorable closure of a four-membered ring competes with the 1,Zring-expansive shift which converts 8 to 9. In the case of sterol biosynthesis from 2,3-oxidosqualene, intermediate 6 undergoes ring expansion to 7 exclusively
吉化集团乙醛酸法合成甲(乙)基香兰素的氧化催化剂获国家专利
由吉 化集 团公 司 开 发 成功 的 乙醛 酸法 合 成 甲 素工艺是 自主研发的具有 自主知识产权的新技术,
( )基 香兰 素 的氧 化催 化剂 ,近 期 获 国家发 明专 工 艺技 术 处 于 国际先 进 水 平 。 开 发 出 的高效 氧 化 乙
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酪乳 、碳酸饮料 和 蜜饯等等 。
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甲 ( )基 香兰 素一 直 是 吉 化集 团 出 口创汇 产 装 置 。 同时还 将 开 发 香兰 素 上 下游 产 品邻 苯二 乙 盈利 的主要 品种 ,乙醛 酸法 新 工艺 甲 ( 乙)基香 兰 酚 、藜芦 酸等 ,形 成吉化 集 团公 司 的优 势产 业 。
诺贝尔化学奖公布一览
诺贝尔化学奖公布一览今年的诺贝尔化学奖公布了一览,涉及的领域涵盖了化学物理学、生物化学、生物物理学和纳米科学等多个方面。
以下将分别介绍获奖人的研究成果。
第一位获奖者是法国科学家Jean-Pierre Sauvage、Sir J. Fraser Stoddart(英)、Bernard L. Feringa(荷兰),获得的诺贝尔化学奖赞扬他们在分子机器方面的杰出工作。
他们在分子构建方面的发展为实现人工分子机器打开了新的可能性。
其中,Jean-Pierre Sauvage的工作是连接两个分子,并让它们能够旋转。
而Sir J. Fraser Stoddart的工作是将双环分子穿上某个分子,并让双环分子能够在分子改变形状时沿着分子轴线自身向上或向下移动。
Bernard L. Feringa的工作是开发了一系列能够在光的作用下转动的分子,这些分子可以不断地重复旋转,执行特定的任务。
第二位获奖者是美国科学家William E. Moerner、艾里克·贝特兹-Bethune、Stefan W. Hell,获得的诺贝尔化学奖赞扬了他们对高分辨率显微镜和单个分子光谱学研究的贡献。
他们的发现被认为是最大的科学进步之一,因为它重新定义了所谓“不可能的分辨率”。
William E. Moerner的发现是单个分子能够在光学显微镜中被检测到。
而艾里克·贝特兹-Bethune和Stefan W. Hell则发现了不同的微学方法,实现了纳米级别的高分辨率成像和量子定义成像,这些方法基于激光和特殊雷射。
第三位获奖者是化学家理查德·赫德,他获得了诺贝尔化学奖,以表彰他们对基因组编辑的重大贡献。
他几十年间一直致力于DNA储存和编辑的研究,致力于开发更加高效精确、更加强大的方法,以编辑和修复基因,并用于治疗和预防疾病。
总之,通过以上介绍,我们可以看到一批化学界的杰出人才,他们的研究为不同领域的学科带来了创新性的飞跃和突破。
陕西启动首个1,4-丁二醇项目
陕西启动首个1,4-丁二醇项目第5期于航等.脱硫醇催化剂磺化酞菁钴稳定性能的改善9参考文献1刘德仿.RFCC汽油纤维膜脱硫新技术及其应用.化工进展, 2004,23(1):88~902杨秀峰.纤维膜接触器在汽油碱洗中的应用.炼油设计,1998,28(6):40~433GB1792—88馏分燃料中硫醇硫测定法.北京:中国标准出版社,1998.2154LeznoffCC,LeverABP.Phalocyanines:propertiesandapplications.VCHPublications,1996,4:285~2965吴星,袁诗海,郑刚等.四磺化酞菁钴在水溶液中的二聚体作用力的研究.光谱学与光谱分析,1999,19(2):112~1146袁诗海,吴星,姚荣等.四磺化酞菁钴轴向配位反应研究.感光科学与光化学,1996,14(4):341~346STUDY oNTHESTABILITY oFSULPHoNA TEDCoBAL T PHTHALoCY ANINACA TAL YSTFoRSWEETENINGPRoCESSY uHang,LiXuhui,XiaDaohong,XiangY uzhi (ChinaUniversityofPetroleum,Dongying257061) AbstractAninvestigationonimprovingthestabilityofsulphonatedcobaltphthalocyanina catalystforsweeteningprocesswascarriedoutusingtechniquessuchasUV—Visspectrumandpotentiometrytitration,tocomparethecatalyticperformanceofalkalinecatal ystsystempriorandposttomodification.Theexperimentalresultsdemonstratedthataddingorganicami neSTlikecomplexcould effectivelyimprovethecatalyststability,keepinghighactivityandprolongin grunningcycle.KeyWords:catalyst;sulphonatedcobaltphthaIocyanina;stability自6砷如盒客盍盍客客客基客盍客客<())《国内简讯;;”)J::{;陕西启动首个1,4-丁二醇项目陕西煤业化工集团所属的陕化股份公司于2006年12月启动了30kt/a1,4一丁二醇(BDO)项目,这是该省第一个BD0项目,预计2008年6月竣工投产.该项目将以陕化股份公司现有的甲醇,氢气等为原料,采用炔醛法工艺技术,一期工程产能为30kt/a,总投资约5亿元人民币,二期工程将于2007年启动.全部建成后,BD0生产规模达60kt/a,从而成为国内主要的BD0生产基地之一.陕化股份公司于2004年建成30kt/a合成氨联产甲醇生产装置,目前正通过技术改造将甲醇产能扩大到100kt/a.BIN)是重要的基本有机化工原料,其衍生物在化工,医药,纺织,工程塑料和日用化工等领域广泛应用.随着我国纺织纤维,电子电气,汽车等行业迅速发展,BIN)市场需求进一步增大.2005年我国BDO生产能力为160kt/a,产量仅75kt/a,远远无法满足市场需求,对外依存度高达5O. [中国石化有机原料科技情报中心站供稿]金浦锦湖100kt/a环氧丙烷一体化项目开工建设江苏南京金浦锦湖石油化工有限公司100kt/a环氧丙烷一体化项目于2006年11月在南京化学工业园正式开工建设.该项目计划总投资约2亿美元,由韩国锦湖石油化学株式会社和江苏金浦集团共同投资建设,分两期完成.一期项目将于2007年底建成投产,包括100kt/a环氧丙烷, 50kt/a聚醚多元醇和100kt/a烧碱装置.二期项目预计形成生产能力为200kt/a环氧丙烷,200kt/a聚醚多元醇, 200kt/a烧碱和175kt/a氯气.[中国石化有机原料科技情报中心站供稿]。
毫微级电子工具
毫微级电子工具
佚名
【期刊名称】《化工文摘》
【年(卷),期】2000(000)008
【摘要】在以色列威茨曼科学院,科学家们研制开发了一种用于高密度、长数据串存储的新方法,这就是毫微级电子工具。
【总页数】1页(P48)
【正文语种】中文
【中图分类】TP333
【相关文献】
1.不定形耐火材料中尖晶石凝胶毫微级显微结构的演变 [J], 李志辉(编译);王晓阳(校)
2.毫赫和毫微赫地震学 [J], 陈培善
3.仿生原型毫-微牛级二维力测试系统研制 [J], 李云鹏; 王立新; 闫世兴; 董世运
4.仿生原型毫-微牛级力测试技术研究进展 [J], 闫征;王立新;潘盼
5.毫微级氧化锆组织热喷涂层弹性模量和显微硬度的评定 [J], 彭补之
因版权原因,仅展示原文概要,查看原文内容请购买。
合成樟脑酸度测定的分析
合成樟脑酸度测定的分析
周海云;廖宏年
【期刊名称】《求医问药(学术版)》
【年(卷),期】2013(011)003
【摘要】目的:为现行版中国药典二部所收载的合成樟脑酸度测定提出建议.方法:按法定方法对3批合成樟脑进行酸度测定并做空白试验,将结果进行分析.结果:由于原标准中未考虑所用溶剂的酸碱性因素,致使对合成樟脑酸度测定的结果有误.结论:应将合成樟脑酸度测定所用的溶剂由乙醇改为中性乙醇或以空白试验对结果加以校正.
【总页数】1页(P77)
【作者】周海云;廖宏年
【作者单位】广西自治区全州县人民医院广西桂林541500
【正文语种】中文
【中图分类】R917
【相关文献】
1.不对称合成ⅩⅥ.(+)-樟脑亚胺的立体控制反应和樟脑结构的研究——(+)-樟脑缩苄胺转动势能计算和构象分析 [J], 邓金根;周昌友;刘桂兰;蒋耀忠;曹泽星;唐作华;鄢国森;周忠远;郁开北
2.紫外分光光度法测定合成樟脑含量 [J], 徐洪杰
3.合成樟脑中樟脑含量测定方法的对比研究 [J], 赵振东;李冬梅;毕良武;王婧;古研;刘先章
4.中,英,德合成樟脑熔点测定方法的比较 [J], 吴小平
5.气相色谱法测定合成樟脑的含量 [J], 邱涵;叶飞云
因版权原因,仅展示原文概要,查看原文内容请购买。
芥子酸分子式
芥子酸分子式引言芥子酸是一种有机化合物,属于羧酸类,化学式为C4H6O4。
它是一种无色结晶固体,可溶于水和乙醇。
芥子酸在生物体内广泛存在,具有多种生理活性和医药应用价值。
本文将详细介绍芥子酸的结构、性质、制备方法以及其在医药领域中的应用。
一、结构芥子酸的分子式为C4H6O4,结构式如下所示:O||H – C – C – OH||O从结构上看,芥子酸中含有一个羧基(-COOH)和一个烯丙基(-CH=CH2)。
这两个基团赋予了芥子酸许多特殊的化学性质。
二、性质1.物理性质:–外观:无色结晶固体;–熔点:152-153℃;–沸点:285℃;–密度:1.53 g/cm³;–溶解性:易溶于水和乙醇。
2.化学性质:–酸性:芥子酸是一种中强酸,能与碱反应生成相应的盐;–氧化性:芥子酸可被氧化剂氧化为二氧化碳和水;–脱水反应:芥子酸在高温下可以脱水生成丙烯酸。
三、制备方法芥子酸的制备方法主要有两种:自然提取和合成。
1.自然提取:芥子酸最常见的自然来源是芥子植物(Brassica juncea)的种子。
通过研磨、浸泡和过滤等工艺,可以从芥子中提取得到芥子油,进而通过加热蒸馏或碱解反应得到芥子酸。
2.合成方法:芥子酸可以通过多种合成途径制备,其中较常用的方法包括:–醛缩反应:将甲基丙二醛与甲基丙二胺缩合,并经过适当条件下的氧化反应得到芥子酸;–氯乙脱羟反应:将3-氯丙二醇与亚硫酰氯反应生成3-氯丙二胺,再与甲醛缩合,最终得到芥子酸。
四、医药应用芥子酸在医药领域中具有多种应用价值,主要包括以下方面:1.抗菌作用:芥子酸具有较强的抗菌活性,可以抑制多种细菌的生长和繁殖。
因此,在医药领域中常被用于制备抗感染、抗炎药物。
2.抗肿瘤活性:研究表明,芥子酸对某些肿瘤细胞具有显著的抑制作用。
其机制可能与其对肿瘤细胞的DNA合成和蛋白质合成的干扰有关。
3.降血脂作用:芥子酸能够促进脂肪代谢,降低血液中的低密度脂蛋白(LDL)水平,减少动脉粥样硬化的发生。
最伟大的天然有机化学家 ——Robert Burns Woodward
最伟大的天然有机化学家——Robert Burns Woodward最伟大的天然有机化学家——Robert Burns Woodward1 Woodward生平简介1917年4月10日Woodward生于美国马萨诸塞州波士顿,从小就对化学抱有浓厚的兴趣,据说他在12岁时就完成了《有机化学的实用方法》(LudwigGattermann’s Practical Methodsof Organic Chemistry)一书中所有的实验。
1933年Woodward就读于麻省理工学院(MassachusettsInstitute of Technology,MIT),入学一年后,由于只专注于化学课程的学习,Woodward其他课程的成绩并不理想,因此一度面临退学。
此时曾主持Woodward面试的JamesFlack Norris教授(1871—1940,认为他是个难得的化学天才,帮助其留在MIT完成了学业,并于1936年取得了学士学位。
取得学士学位一年后的1937年,年仅20岁的Woodward又获得了博士学位,毕业论文是《麦角酸的研究》(Studieson lysergic acid),导师是James Flack Norris教授与AveryAdrian Morton教授(1892—1987,在这期间Woodward还完成了雌激素酮(estrone,1,图3)的合成[1]。
毕业后的Woodward于1937在伊利诺伊大学(University of Illinois)担任了一段时间博士研究员(instructorship),同年夏天回到哈佛大学任Elmer Peter Kohler教授(1865—1938)的研究助理,一年后成为哈佛研究员协会(Harvard Societyof Fellows)初级会员。
1941年1月Woodward成为哈佛大学化学系讲师,于1944年晋升为助理教授;1946年,29岁的Woodward升为副教授,并被聘为终身教授(tenured professor),1950年升为正教授,终生在哈佛任教。
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Fell1
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Hs
oxy-6(E),8,11,14(Z)-eicosatetraenoicacid (5-S-HPETE, l),and (2) the transformation of 5-S-HPETE to leukotriene Ad (LTA,, 2).' Evidence has been obtained that the 5 - L 0 , either from murine mast cells2 or from pot at^,^,^ catalyzes the conversion of ara( I ) See: The Leukotrienes, Chemistry and Biology, Chakrin, L. W., Bailey, D. M., Eds.; Academic Press: New York, 1984. (2) Shimizu, T.; Izumi, T.; Seyama, Y.; Tadokoro, K.; RBdmark, 0.; Samuelsson, B. Proc. Natl. Acad. Sci. U.S.A.1986.83.4175-4179. Because LTA, undergoes rapid hydrolysis in neutral aqueous media, it was not isolated from incubation experiments but was analyzed as the mixture of 5,6- and
Stereochemistry and Mechanism of the Biosynthesis of Leukotriene A4 from 5( S)-Hydroperoxy-6(E),8,11,14(Z)-eicosatetraenoic Acid. Evidence for an Organoiron Intermediate
E. J. Corey,* Stephen W. Wright, and Seiichi P. T. Matsuda
Contribution from the Department o f Chemistry, Harvard University, Cambridge, Massachusetts 02138. Received July 5, 1988
(40) (a) Zimmerman, S. C.; Cramer, K. D. J . Am. Chem. SOC. 1988,110, 5906. (b) Huff, J. B.; Askew, B.; Duff, R. J.; Rebek, J., Jr. Ibid. 1988, 110, 5908.
Abstract: The pathway of biosynthesis of leukotriene A4 (LTA4, 2) from 5(S)-hydroperoxy-6(E),8,11,14(Z)-eicosatetraenoic
acid (5-S-HPETE, 1) has been explored by the comparative study of (S)- and (R)-lipoxygenase (LO) enzymes as catalysts. The purified L O from potato, an S-lipoxygenase, converts (anaerobically) 1 to 2 (determined as the characteristic hydrolysis mixture of two epimeric 5,6-diols and two epimeric 5,12-diols), as previously reported by Samuelsson et al. However, the 8-R-LO from the coral Plexaura homomalla transforms 1 (anaerobically) into 6-epi-LTA4 ( 6 ) . The observed divergence of stereopathways agrees with predictions based on the intermediacy of organoiron intermediates in enzymic lipoxygenation (Scheme I) and detailed in Schemes I1 and 111. Further evidence for the intervention of such intermediates has been obtained by trapping experiments under pure O2 a t pressures of 1-60 atm. Under O2 pressure 1 is converted by the potato L O to a new product, the bis(hydroper0xide) 7, whereas the coral L O converts 1 to the diastereomeric bis(hydroper0xide) 9. The biosynthesis of the physiologically and medically important leukotrienes' from arachidonate is initiated by two processes which interest: (1) tthe conversion of a r e also of great arachidonate by a mechanistic (5s)-lipoxygenase (5-LO) o 5(S)-hydroperScheme I
(41) The basicity argument requires that a proton be transfered from the proximal imidazole N-H to carboxylate concurrent with the distal N: acting as a general base on SerOH. This is thermodynamically favorable only if the normal pK, values of imidazolium and the carboxylic acid be reversed in the enzyme active site as the transition state for the acylation is appr~ached.~
1452
H I I
J . Am. Chem. S o t . 1989, 1 1 1 , 1452-1455
arrangement places the center of (-)-charge in the carboxylate closer to the imidazole H-N thereby optimizing the electrostatic interaction. T o term this system a model for the acylation of the SPases invites comparison with the enzyme which may not be justified given the unorthodox geometry of the acylating agent and perhaps non-optimal alignment of the functional groups in serine or 2d. Furthermore, even with the enzymes the mechanism of acylation shows subtle substrate dependent diversities so that in some cases t h e Asp COT may act electrostatically and in others it may act as a bonafide general base.l What is certain from the above study is a demonstration of a role for carboxylate t h a t enhances the amine basicity and allows the latter to more effectively influence direct C H z O H acylation. This may be viewed as a small molecule precedent for a similar role suggested to occur in the S P a ~ e s . ~
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T h e study also shows t h a t the carboxylate in 2d, although not optimally aligned with the imidazole in the sense described by Gandour,26 enhances the imidazole basicity by 1.2 pK, units relative to comparison ester 2e. For imidazolium ionizations wherein an intramolecular carboxylate is syn oriented, reference has been made to large ApK, values in comparison with a corresponding imidazolium esteraa or other comparison materials40b containing an anti disposed carboxylate- - -imidazolium couple. However, the data herein indicate t h a t a syn orientation is not required for a large ApK,. Moreover, we note that large ApK, values are conditional upon the nature of the amine (e.g., pK," serineethyl serinate = 2.06, Table I ) and solvation (e.g., pKaLm--H+ 2d-2e is 7.45 - 6.02 = 1.43 in 40% E t O H / H 2 0 and 7.33 - 5.74 = 1.59 in 80% E t O H / H 2 0 ) . A syn orientation of the carboxylate may be of evolutionary advantage t o the enzymes t h a t employ it not only for the basicity argument^^^.^^ but also because t h a t