Digestive Activity of Lysosomes

作者：Stanley Fowler, C. De Duve · 发表于：Journal of Biological Chemistry · 年份：1969 · DOI：10.1016/s0021-9258(18)94453-4 · 被引用次数：252 · 研究领域：Biomedical Research and Pathophysiology、Lysosomal Storage Disorders Research、Sphingolipid Metabolism and Signaling

Abstract The ability of rat liver lysosomes to digest various lipids has been investigated. The lysosomes were isolated from the livers of rats treated with Triton WR-1339 and were essentially free of other cell components. They were able to deacylate extensively phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, lysophosphatidylcholine, lysophosphatidylethanolamine, phosphatidic acid, cardiolipin, tripalmitin, 1,2-dipalmitin, 1,3-dipalmitin, and 1-monopalmitin, when incubated with these substrates at 37° in 0.1 m acetate buffer, pH 4.3 to 4.6. With most substrates, hydrolysis occurred without the addition of a detergent. Exceptions were tripalmitin, which was not attacked in the absence of detergent, but was deacylated vigorously in the presence of 5% Triton X-100, and cardiolipin, which required addition of 0.1% Triton X-100 for hydrolysis in acetate buffer, but was attacked in citrate buffer without added detergent. The hydrolysis of diglycerides was stimulated by 5% Triton X-100. On the other hand, this detergent inhibited the deacylation of phosphatidylethanolamine and of monopalmitin. Sphingomyelin was not deacylated, but was hydrolyzed to ceramide and phosphorylcholine. Hydrolysis of ceramide could not be established, either with lysosomes or with whole liver preparations, under a variety of conditions. The phosphodiesters arising from the digestion of phospholipids proved to be resistant to lysosomal hydrolysis, both at acid and a...