Winkler J D, Sung C M, Huang L
Department of Pharmacology, SmithKline Beecham Pharmaceutials, King of Prussia, PA 19406.
Agents Actions. 1991 Sep;34(1-2):103-5. doi: 10.1007/BF01993250.
CoA-independent transacylase (CoA-IT) catalyzes the transfer of arachidonic acid from acyl- to alkyl-linked phospholipids. The removal of arachidonic acid from the sn-2 position of the donor phospholipid is a PLA2-like reaction. However, examination of CoA-IT in U937 cells demonstrated that CoA-IT has many characteristics that are distinct from those of PLA2 enzymes, including activity in the absence of Ca2+, activity that was heat and acid unstable and stable in 10 mM 2-mercaptoethanol and that was inhibited by detergents. Compounds that inhibit PLA2 activity did not inhibit CoA-IT activity, including quinacrine, aristolochic acid and arachidonic acid. All of these characteristics of CoA-IT are in contrast to those of most PLA2 enzymes. These data suggest that CoA-IT is biochemically different from, and has a mechanism of action unique from PLA2 enzymes.
不依赖辅酶A的转酰基酶（CoA-IT）催化花生四烯酸从酰基连接的磷脂转移至烷基连接的磷脂。从供体磷脂的sn-2位去除花生四烯酸是一种类似磷脂酶A2（PLA2）的反应。然而，对U937细胞中的CoA-IT进行检测发现，CoA-IT具有许多与PLA2酶不同的特性，包括在无Ca2+时具有活性、该活性对热和酸不稳定而在10 mM 2-巯基乙醇中稳定，并且会被去污剂抑制。抑制PLA2活性的化合物不会抑制CoA-IT活性，包括奎纳克林、马兜铃酸和花生四烯酸。CoA-IT的所有这些特性都与大多数PLA2酶的特性形成对比。这些数据表明，CoA-IT在生化性质上与PLA2酶不同，并且具有独特的作用机制。
