Waite M, Scherphof G L, Boshouwers F M, van Deenen L L
J Lipid Res. 1969 Jul;10(4):411-20.
Highly purified mitochondria from rat liver contain a phospholipase A that catalyzes removal of 2-fatty acids, with a pH optimum above pH 8.0. Lysosomal preparations appeared to have two phospholipases A associated with them, one with a pH optimum at about pH 4.0, the second between pH 6.0 and 7.0. Mitochondrial phospholipase A hydrolyzed exogenous phospholipid as fast as or faster than endogenous phospholipid. The difference in specific radioactivity of (14)C-ethanolamine-labeled endogenous mitochondrial phospholipid before and after incubation indicates that a fraction of mitochondrial phosphatidyl ethanolamine is hydrolyzed more rapidly than the mitochondrial phospholipids as a whole. Acyl bond hydrolysis of exogenous and endogenous phospholipid by mitochondria was stimulated by free fatty acid, Ca(++), or in certain cases, monoacyl phospholipids or by treatments that disrupt the mitochondrial membrane. Of various fatty acids tested, lauric, myristic, oleic, and linoleic were most effective. ADP and ATP inhibited mitochondrial phospholipase, probably because they compete for Ca(++). Mg(++) also behaved as a competitive inhibitor; the effect was overcome by relatively little Ca(++).
从大鼠肝脏中高度纯化的线粒体含有一种磷脂酶A，它催化去除2-脂肪酸，最适pH值高于8.0。溶酶体制剂似乎有两种与之相关的磷脂酶A，一种最适pH值约为4.0，另一种在pH值6.0至7.0之间。线粒体磷脂酶A对外源磷脂的水解速度与内源磷脂相同或更快。孵育前后（14）C-乙醇胺标记的内源性线粒体磷脂的比放射性差异表明，线粒体磷脂酰乙醇胺的一部分比整个线粒体磷脂水解得更快。线粒体对外源和内源磷脂的酰基键水解受到游离脂肪酸、Ca（++）的刺激，或在某些情况下受到单酰基磷脂的刺激，或受到破坏线粒体膜的处理的刺激。在测试的各种脂肪酸中，月桂酸、肉豆蔻酸、油酸和亚油酸最为有效。ADP和ATP抑制线粒体磷脂酶，可能是因为它们竞争Ca（++）。Mg（++）也表现为竞争性抑制剂；相对少量的Ca（++）就能克服这种影响。
