Selective incorporation of polyunsaturated fatty acids into phosphatidylcholine by rat liver microsomes.
Selective incorporation of polyunsaturated fatty acids into phosphatidylcholine by rat liver microsomes.
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DOI：
10.1016/s0021-9258(18)33378-7
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发表时间：
1982-12
期刊：
影响因子：
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通讯作者：
W. Lands;M. Inoue;Y. Sugiura;H. Okuyama
中科院分区：
文献类型：
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作者：
W. Lands;M. Inoue;Y. Sugiura;H. Okuyama
在细胞脂质中发现的各种多不饱和脂肪酸从它们的辅酶A硫醇酯转移到磷脂受体的最大速度有很大不同。硫羟酸酯酰化1-酰基甘油-3-磷酸胆碱的表观Km值非常低，不能直接测量，但它们的值可以相对于花生四烯酸酯进行估计。各种多不饱和酰基辅酶A的竞争有效性通过测量允许与花生四烯酰辅酶A相等的缩合的等效浓度来估计。这些值有助于预测的方式，其中各种多不饱和酰基辅酶A可以选择性酯化膜脂质的1-酰基甘油3-磷酸胆碱（1-酰基-GPC）酰基转移酶系统的肝微粒体。饱和酸的酰基-CoA酯以及22：1、22：2和22：3的酰基-CoA酯竞争1-酰基-GPC酰基转移酶系统的活性位点的能力可以忽略不计。花生四烯酸酯（20：4 n-6）、二十碳三烯酸酯（20：3 n-6）、二十碳五烯酸酯（20：5 n-3）和亚麻酸酯的两种异构体（18：3 n-6和n-3）的酰基-CoA酯优先被1-酰基-GPC酰基转移酶处理。来自肝脏的系统对不饱和酸有很高的选择性，但似乎不能区分作为白藜芦醇和白三烯前体的n-6和n-3系列的多不饱和酸。
The various polyunsaturated fatty acids found in cellular lipids are transferred from their coenzyme A thiol esters to phospholipid acceptors with greatly different maximal velocities. The very low apparent Km values for the thiol esters in acylating 1-acylglycerol-3-phosphocholine could not be directly measured, but their values could be estimated relative to that for arachidonate. The competitive effectiveness of various polyunsaturated acyl-CoAs was estimated by measuring the equivalent concentrations which allow incorporations equal to arachidonyl-CoA. These values help predict the way in which various polyunsaturated acyl-CoAs may be selectively esterified to membrane lipids by the 1-acylglyceol 3-phosphocholine (1-acyl-GPC) acyltransferase system of liver microsomes. The acyl-CoA esters of saturated acids, as well as those for 22:1, 22:2, and 22:3, had negligible ability to compete for the active sites of the 1-acyl-GPC acyltransferase system. The acyl-CoA esters of arachidonate (20:4n-6), eicosatrienoate (20:3n-6), eicosapentaenoate (20:5n-3), and both isomers of linolenate (18:3n-6 and n-3) were handled preferentially by the 1-acyl-GPC acyltransferases. The system from liver has a high selectivity for unsaturated acids but does not appear to discriminate among the polyunsaturated acids of the n-6 and n-3 series that serve as precursors of prostaglandins and leukotrienes.