Ariyoshi H, Shiba E, Sakon M, Kambayashi J, Kawasaki T, Kang J, Kawashima S, Mori T
Department of Surgery II, Osaka University Medical School, Japan.
Biochem Int. 1992 Jul;27(2):335-41.
The binding of calpain-I (Ca2+ activated neutral protease with high Ca2+ sensitivity) to the membranes of human platelets and the subsequent autolytic activation of calpain-I were analyzed by an immunoblot technique. In A23187 stimulated platelets, cytosolic calpain-I translocated to the membranes with autolysis in a Ca2+ dependent manner and simultaneously underwent autolysis. Although calpeptin, a cell permeable calpain inhibitor, inhibited autolysis of calpain-I, it was unable to prevent the translocation of calpain-I. In a cell re-constituted system, the membrane binding of calpain-I was also Ca2+ dependent and was significantly inhibited by a substrate of calpain. It was suggested that the binding of calpain-I to the membranes required the substrate binding site of this enzyme.
采用免疫印迹技术分析了钙蛋白酶-I（对Ca2+高度敏感的Ca2+激活中性蛋白酶）与人血小板膜的结合以及随后钙蛋白酶-I的自溶激活。在A23187刺激的血小板中，胞质钙蛋白酶-I以Ca2+依赖的方式转位至膜上并自溶，同时发生自溶。尽管细胞可渗透的钙蛋白酶抑制剂钙肽素抑制了钙蛋白酶-I的自溶，但它无法阻止钙蛋白酶-I的转位。在细胞重构系统中，钙蛋白酶-I与膜的结合也是Ca2+依赖的，并被钙蛋白酶的一种底物显著抑制。提示钙蛋白酶-I与膜的结合需要该酶的底物结合位点。
