Arthur G, Choy P C
Biochem J. 1986 Jun 1;236(2):481-7. doi: 10.1042/bj2360481.
The deacylation-reacylation process has been shown to be an important pathway for phospholipids to attain the desired acyl groups at the C-2 position. The acylation of 1-acyl-glycerophosphocholine (-GPC) in mammalian hearts has been well documented, but the acylation of 1-alkenyl-GPC has not been described. In this paper, we demonstrate the presence of acyl-CoA: 1-alkenyl-GPC acyltransferase for the acylation of 1-alkenyl-GPC in mammalian hearts; the highest activity is found in guinea pig heart. The guinea pig heart 1-alkenyl-GPC acyltransferase has only 10-40% of the 1-acyl-GPC acyltransferase activity, and both activities are located in the microsomal fraction. However, these two enzymes respond differently to cations, detergents and heat treatment, and the two enzymes also display different acyl specificity. Kinetic studies indicate that both reactions could not be accommodated by the same catalytic site. The results provide strong evidence that the two activities are from separate and distinct proteins. The specificity of 1-alkenyl-GPC acyltransferase for unsaturated species of acyl-CoA may play an important role in the maintenance of the high degree of unsaturated acyl groups found in guinea pig heart plasmalogens.
脱酰基-再酰基化过程已被证明是磷脂在C-2位获得所需酰基的重要途径。哺乳动物心脏中1-酰基甘油磷酸胆碱（-GPC）的酰基化已有充分记录，但1-烯基-GPC的酰基化尚未见报道。在本文中，我们证明了在哺乳动物心脏中存在酰基辅酶A：1-烯基-GPC酰基转移酶用于1-烯基-GPC的酰基化；在豚鼠心脏中发现活性最高。豚鼠心脏1-烯基-GPC酰基转移酶的活性仅为1-酰基-GPC酰基转移酶活性的10%-40%，且两种活性均位于微粒体部分。然而，这两种酶对阳离子、去污剂和热处理的反应不同，并且这两种酶还表现出不同的酰基特异性。动力学研究表明，这两种反应不能由同一个催化位点来完成。结果提供了有力证据，表明这两种活性来自不同的蛋白质。1-烯基-GPC酰基转移酶对不饱和酰基辅酶A物种的特异性可能在维持豚鼠心脏缩醛磷脂中高度不饱和酰基的过程中起重要作用。
