来自发芽豌豆的颗粒制剂进行的脂肪酸生物合成

Fatty acid biosynthesis by a particulate preparation from germinating pea.

作者信息

Bolton P, Harwood J L

出版信息

Biochem J. 1977 Nov 15;168(2):261-9. doi: 10.1042/bj1680261.

DOI:10.1042/bj1680261

PMID:579600

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1183759/

Abstract

Fatty acid synthesis was studied in microsomal preparations from germinating pea (Pisum sativum). 2. The preparations synthesized a mixture of saturated fatty acids up to a chain length of C(24) from [(14)C]malonyl-CoA. 3. Whereas hexadecanoic acid was made de novo, octadecanoic acid and icosanoic acid were synthesized by elongation. 4. The products formed during [(14)C]malonyl-CoA incubation were analysed, and unesterified fatty acids and polar lipids were found to be major products. [(14)C]Palmitic acid represented a high percentage of the acyl-carrier protein esters, whereas (14)C-labelled very-long-chain fatty acids were mainly present as unesterified fatty acids. CoA esters were minor products. 5. The addition of exogenous lipids to the incubation system usually resulted in stimulation of [(14)C]malonyl-CoA incorporation into fatty acids. The greatest stimulation was obtained with dipalmitoyl phosphatidylcholine. Both exogenous palmitic acid and dipalmitoyl phosphatidylcholine increased the amount of [(14)C]-stearic acid synthesized, relative to [(14)C]palmitic acid. Addition of stearic acid increased the amount of [(14)C]icosanoic acid formed. 6. [(14)C]Stearic acid was elongated more effectively to icosanoic acid than [(14)C]stearoyl-CoA, and its conversion was not decreased by addition of unlabelled stearoyl-CoA. 7. Incorporation of [(14)C]malonyl-CoA into fatty acids was markedly decreased by iodoacetamide and 5,5'-dithiobis-(2-nitrobenzoic acid). Palmitate elongation was sensitive to arsenite addition, and stearate elongation to the presence of Triton X-100 or fluoride. The action of fluoride was not, apparently, due to chelation. 8. The microsomal preparations differed from soluble fractions from germinating pea in (a) synthesizing very-long-chain fatty acids, (b) not utilizing exogenous palmitate-acyl-carrier protein as a substrate for palmitate elongation and (c) having fatty acid synthesis stimulated by the addition of certain complex lipids.

摘要

对发芽豌豆（豌豆）微粒体制剂中的脂肪酸合成进行了研究。2. 这些制剂从[¹⁴C]丙二酰辅酶A合成了链长至C(24)的饱和脂肪酸混合物。3. 十六烷酸是从头合成的，而十八烷酸和二十烷酸是通过延长合成的。4. 分析了在[¹⁴C]丙二酰辅酶A孵育过程中形成的产物，发现未酯化脂肪酸和极性脂质是主要产物。[¹⁴C]棕榈酸在酰基载体蛋白酯中占很高比例，而¹⁴C标记的超长链脂肪酸主要以未酯化脂肪酸形式存在。辅酶A酯是次要产物。5. 向孵育系统中添加外源脂质通常会刺激[¹⁴C]丙二酰辅酶A掺入脂肪酸。用二棕榈酰磷脂酰胆碱获得的刺激最大。外源棕榈酸和二棕榈酰磷脂酰胆碱相对于[¹⁴C]棕榈酸都增加了[¹⁴C]硬脂酸的合成量。添加硬脂酸增加了[¹⁴C]二十烷酸的形成量。6. [¹⁴C]硬脂酸比[¹⁴C]硬脂酰辅酶A更有效地延长为二十烷酸，并且添加未标记的硬脂酰辅酶A不会降低其转化率。7. 碘乙酰胺和5,5'-二硫代双-(2-硝基苯甲酸)显著降低了[¹⁴C]丙二酰辅酶A掺入脂肪酸的量。棕榈酸延长对亚砷酸盐的添加敏感，硬脂酸延长对Triton X-100或氟化物的存在敏感。氟化物的作用显然不是由于螯合。8.微粒体制剂与发芽豌豆的可溶部分的不同之处在于：(a) 合成超长链脂肪酸；(b) 不利用外源棕榈酸-酰基载体蛋白作为棕榈酸延长的底物；(c) 添加某些复合脂质会刺激脂肪酸合成。