Waite M, Van Deenen L L, Ruigrok T J, Elbers P F
J Lipid Res. 1969 Sep;10(5):599-608.
Assays of mitochondrial phospholipase A activity and mitochondrial swelling demonstrated that the phospholipase A activity is related to the swelling under the experimental conditions used. Both were stimulated by added free fatty acid and CaCl(2), not affected greatly by the addition of monoacyl phosphoglycerides, and inhibited by EDTA. The amount of fatty acid hydrolyzed from endogenous phosphatidyl ethanolamine and phosphatidyl choline during swelling was calculated to be 20-30 times less than the amount of added free fatty acid that gave comparable swelling. Under the experimental conditions about 4% of the phospholipid was hydrolyzed. Mitochondrial swelling was studied by electron microscopy and turbidity measurements. The results found were in agreement, whether oleic acid was present or not, except for those values obtained after very brief incubation (1 min) and after incubation for longer than 35 min. The lack of direct proportion between swelling and the concentration of lysosomes present indicated that the swelling is related mainly to mitochondrial phospholipase A, although swelling due to contaminating lysosomes cannot be excluded entirely. The temperature dependence of spontaneous, fatty acid-induced, or CaCl(2)-induced swelling suggested that enzymatic activities are responsible for swelling.
线粒体磷脂酶A活性测定和线粒体肿胀实验表明，在所采用的实验条件下，磷脂酶A活性与肿胀有关。二者均受到添加的游离脂肪酸和CaCl₂的刺激，单酰磷酸甘油酯的添加对其影响不大，且受到EDTA的抑制。肿胀过程中从内源性磷脂酰乙醇胺和磷脂酰胆碱水解得到的脂肪酸量经计算比产生相当肿胀程度的添加游离脂肪酸量少20 - 30倍。在实验条件下，约4%的磷脂被水解。通过电子显微镜和浊度测量研究了线粒体肿胀情况。无论是否存在油酸，所得到的结果都是一致的，但在极短时间孵育（1分钟）后以及孵育超过35分钟后得到的值除外。肿胀与存在的溶酶体浓度之间缺乏直接比例关系，这表明肿胀主要与线粒体磷脂酶A有关，尽管不能完全排除因污染的溶酶体导致的肿胀。自发的、脂肪酸诱导的或CaCl₂诱导的肿胀对温度的依赖性表明酶活性是肿胀的原因。
