Evidence for two separate beta-ketoacyl CoA reductase components of the hepatic microsomal fatty acid chain elongation system in the rat.
Evidence for two separate beta-ketoacyl CoA reductase components of the hepatic microsomal fatty acid chain elongation system in the rat.
复制标题
大鼠肝微粒体脂肪酸链延长系统中两个独立的 β-酮脂酰 CoA 还原酶成分的证据。
DOI：
10.1016/0006-291x(89)91547-7
复制
发表时间：
1989
影响因子：
3.1
通讯作者：
Cinti,DL
中科院分区：
文献类型：
--
作者：
Nagi,MN;Cook,L;Suneja,SK;Peluso,PS;Laguna,JC;Osei,P;Cinti,DL
肝微粒体脂酸链延长系统可以利用NADPH或NADH。以丙二酰辅酶A掺入棕榈酰辅酶A的速率衡量的延伸活性，在使用任何一种辅因子的情况下，都可以通过脱脂饲料和牛血清白蛋白(BSA)来增强。当测定中间产物时，观察到在牛血清白蛋白和NADPH存在下，主要产物是饱和伸长脂肪酸，而在牛血清白蛋白和NADH存在下，主要中间产物是β-酮酰基衍生物。以β-酮酰辅酶A为底物，牛血清白蛋白显著抑制NADH支持的β-酮酰辅酶A还原酶活性，刺激NADPH支持的活性。此外，依赖于NADH和依赖于NADPH的β-酮还原酶的活性之和接近于这两种辅因子存在时的活性，这表明存在两种β-酮酰辅酶A还原酶，一种利用NADH，另一种利用NADPH。
The hepatic microsomal fatty acid chain elongation system can utilize either NADPH or NADH. Elongation activity, measured as the rate of malonyl CoA incorporation into palmitoyl CoA, was enhanced by a fat-free diet and by bovine serum albumin (BSA) when either cofactor was employed. When the intermediate products were determined, it was observed that in the presence of BSA and NADPH, the predominant product was the saturated elongated fatty acid, whereas in the presence of BSA and NADH, the major intermediate was the β-ketoacyl derivative. Employing β-ketostearoyl CoA as substrate, BSA markedly inhibited NADH-supported β-ketoacyl CoA reductase activity and stimulated NADPH-supported activity. Furthermore, the sum of the NADH-dependent and NADPH-dependent β-ketoreductase activities approximated the activity obtained when both cofactors were present in the incubation medium, suggesting the existence of two β-ketoacyl CoA reductases, one using NADH and the other, NADPH.