Miwa M, Ichihashi T, Motojima H, Onodera-Kubota I, Matsumoto M
J Biochem. 1985 Jul;98(1):157-65. doi: 10.1093/oxfordjournals.jbchem.a135254.
Non-competitive inhibition of snake venom phospholipase A2 which has been exhibited by bovine plasma phospholipase A inhibitor, a kind of lipoprotein, was not observed unless the inhibitor was preincubated with the enzyme. The inhibition seemed to be due to the formation of the enzyme-inhibitor complex, which was identified by immunoelectrophoresis. The enzyme-inhibitor interaction was observed maximally on incubation at physiological pH, but not below pH 5. The inhibitor was inactivated by trypsin digestion and heat treatment. It suppressed the phospholipase A2 activities of rat blood plasma as well as of the snake venom and porcine pancreas, but not the enzyme activities such as those of phospholipase C of Bacillus cereus, lipase of porcine pancreas, trypsin, and papain. The inhibitor also showed the ability to decrease membrane-bound phospholipase A1 and A2 activities in intracellular organelles such as plasma membranes, mitochondria, lysosomes, and microsomes. In view of these facts, it was concluded that the plasma inhibitor is specific for phospholipase A.
牛血浆磷脂酶A抑制剂（一种脂蛋白）对蛇毒磷脂酶A2的非竞争性抑制作用，除非该抑制剂与酶预先孵育，否则不会出现。这种抑制作用似乎是由于酶-抑制剂复合物的形成，通过免疫电泳鉴定。在生理pH下孵育时，酶-抑制剂相互作用最为明显，但在pH 5以下则不然。该抑制剂可被胰蛋白酶消化和热处理灭活。它抑制大鼠血浆以及蛇毒和猪胰脏的磷脂酶A2活性，但不抑制诸如蜡样芽孢杆菌的磷脂酶C、猪胰脏的脂肪酶、胰蛋白酶和木瓜蛋白酶等酶的活性。该抑制剂还表现出降低细胞内膜结合的磷脂酶A1和A2活性的能力，这些细胞器如质膜、线粒体、溶酶体和微粒体。鉴于这些事实，可以得出结论，血浆抑制剂对磷脂酶A具有特异性。
