Kinetic parameters of lysophospholipid acyltransferase systems in diet-induced modifications of platelet phospholipid acyl chains.
Kinetic parameters of lysophospholipid acyltransferase systems in diet-induced modifications of platelet phospholipid acyl chains.
复制标题
饮食诱导的血小板磷脂酰基链修饰中溶血磷脂酰基转移酶系统的动力学参数。
DOI：
10.1248/cpb.36.2109
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发表时间：
1988
影响因子：
1.7
通讯作者：
H. Okuyama
中科院分区：
文献类型：
--
作者：
S. Murase;K. Yamada;H. Okuyama
测定了多不饱和脂肪酸在血小板膜酰基-辅酶A：溶血磷脂酰基转移酶体系中的竞争效率和相对Km值。在体外实验中，18：2N-6(亚油酸)、18：3N-3(α-亚麻酸)、18：3N-6、20：3N-6(二高-γ-亚麻酸)、20：5N-3(二十碳五烯酸)等辅酶A酯是花生四烯酸(20：4N-6)掺入磷脂酰胆碱的较好竞争性抑制剂，而在溶血磷脂酰肌醇的酰化反应中，18：2N-6、20：2N-6、20：3N-6、20：5N-3和22：4N-6是相对较好的抑制剂。当饲喂高达18：2n-6或18：3n-3的植物油饲料时，这些脂肪酸被转化为20：4n-6和20：5n-3等高度不饱和脂肪酸，并被酯化为血小板中的磷脂。体外测定的动力学参数可用于预测二十烷类前体(20：4n-6和20：5n-3)的相对丰度，但不能预测18碳多不饱和脂肪酸的相对丰度。结果发现，在18：2n-6和18：3n-3不同比例的饲料中，大鼠血小板中花生四烯酸是保守的，但n-3脂肪酸在磷脂酰肌醇中比在磷脂酰胆碱中更严格地被排除。
Competitive effectiveness and relative Km values of polyunsaturated fatty acids were determined in the acyl-CoA : lysophospholipid acyltransferase systems in platelet membranes. Some CoA esters of fatty acids such as 18 : 2n-6 (linoleic), 18 : 3n-3(α-linolenic), 18 : 3n-6, 20 : 3n-6 (dihomo-γ-linolenic) and 20 : 5n-3 (eicosapentaenoic) were found in vitro to be relatively good competitive inhibitors of arachidonate (20 : 4n-6) incorporation into phosphatidylcholine, while in the acylation of lysophosphatidylinositol, 18 : 2n-6, 20 : 2n-6, 20 : 3n-6, 20 : 5n-3 and 22 : 4n-6 were relatively good inhibitors. When vegetable oil-supplemented diets rich in 18 : 2n-6 or 18 : 3n-3 were fed to rats, these fatty acids were converted to highly unsaturated fatty acids such as 20 : 4n-6 and 20 : 5n-3, and were esterified to phospholipids in platelets. The kinetic parameters determined in vitro were useful in predicting grossly the relative abundance of eicosanoid precursors (20 : 4n-6 and 20 : 5n-3), but not that of 18-carbon polyunsaturated fatty acids. It was found that arachidonate was conserved but n-3 fatty acids were excluded relatively more strictly in phosphatidylinositol than in phosphatidylcholine in platelets of rats on diets containing different proportions of 18 : 2n-6 and 18 : 3n-3.