脂肪酸从头合成翻译

Abbreviations: ACP, acyl carrier protein; BC, biotin carboxylase domain; BCCP, biotin carboxyl carrier protein; CT, carboxyl transferase domain; DAGAT, diacylglycerol acyltransferase; DAP, day after pollination; DW, dry weight; EM, embryo morphogenesis; ENR, enoyl-ACP reductase; EREBP, ethylene responsive element- binding protein; FAE, fatty acid elongase complex; FAS, fatty acid synthase; HD, hydroxyacyl-ACP dehydratase; HtACCase, heteromeric acetyl-Coenzyme A carboxylase; KAR, 3-ketoacyl-ACP reductase; KAS, 3-ketoacyl-ACP synthase; LPD, lipoamide dehydrogenase; MAT, malonyltransferase; OPPP, oxidative pentose phosphate pathway; PDC, pyruvate dehydrogenase complex; PDH, pyruvate dehydrogenase; PEP, phosphoenolpyruvate; PKp, plastidic pyruvate kinase; PUFA, polyunsaturated fatty acid; SSP, seed storage protein; RuBisCO, ribulose-1,5- bisphosphate carboxylase/oxygenase; TAG, triacylglycerol; VLCFA, very long-chain fatty acid.

缩写:ACP、酰基载体蛋白;BC,生物素羧化酶域;BCCP,生物素羧基载体蛋白;CT, 羧基转移酶域;DAGAT, 二酰基甘油酰基转移酶,DAP,授粉后天数;DW,干重,EM,胚胎形态发生;ENR, 烯酰-ACP还原酶;EREBP, 乙烯反应元件结合蛋白;FAE,脂肪酸延长酶复合体;FAS,脂肪酸合成酶,HD, 羟烷基-ACP脱水酶;HtACCase,杂聚肽乙酰辅酶A羧化酶;KAR,3-酮脂酰-ACP还原酶;KAS,3-酮脂酰-ACP合成酶;LPD, 硫辛酰胺脱氢酶;MAT，丙二酰转移酶;OPPP,氧化磷酸戊糖途径;PDC,丙酮酸脱氢酶复合体;PDH，丙酮酸脱氢酶;PEP,磷酸烯醇丙酮酸;PKp,质体丙酮酸激酶;PUFA,多不饱和脂肪酸;SSP,种子贮藏蛋白; RuBisCO,核酮糖-1,5 -二磷酸羧化酶/加氧酶;TAG,三酰甘油;VLCFA，极长链脂肪酸。

So far, the small size of A. thaliana seeds has prevented to characterise in a detailed manner the organic compounds delivered to the maturing embryos. In seeds of the related B. napus species, these compounds mainly consist of sucrose, glucose, Gln, Glu, and Ala [21–23].Once transported into embryo cells, incoming sucrose can be cleaved via two distinct pathways involving either invertase or sucrose synthase [24–26]. Cleavage of sucrose generates hexose- phosphates that are metabolised through the oxidative pentose phosphate pathway (OPPP) and the glycolytic pathway, providing precursors for fatty acid production in the form of acetyl-CoA.Glycolysis is considered as the predominant pathway for the production of these precursors. In oilseeds, maturing embryos do have a complete glycolytic sequence in the cytosol and in plastids [27–29]. The extent to which both glycolytic sequences are utilised in the conversion of hexose-phosphates into precursors of fattyacid biosynthesis is still a matter of debate. Sets of ESTs from developing A. thaliana seeds [29] and microarrays displaying seed-expressed genes [30,31] have been produced.The data sets thus generated suggest that a major route for the metabolism of hexose-phosphates involves the cytosolic glycolytic pathway up to phospho- enolpyruvate (PEP), this compound being massively imported into the plastid before conversion to pyruvate [32]Nevertheless, when considering the substrate specificities of the two PEP transporters identified in A. thaliana, namely AtPPT1 and AtPPT2 [33], it is tempting to speculate that low amounts of 2-phosphoglycerate and 3-phosphoglycerate may also be transported into the plastids (Fig. 2).T he ADP-dependent conversion of PEP to pyruvate and ATP is catalysed by plastidic pyruvate kinase (PKp).The enzyme prevalent in the plastids of developing seeds likely has a subunit composition of 4a4b1 [34], and the characterisation of Pkp-a–Pkp- b1 double mutants producing wrinkled seeds severely depleted in storage lipids has further established the importance of the plastid route in the conversion of PEP into precursors of fattyacid synthesis [35].The irreversible oxidative decarboxylation of pyruvate to produce acetyl-CoA, NADH, and CO2 is catalysed by the plastid