钙依赖性蛋白酶的蛋白质抑制剂：从牛心组织中的纯化及其可能的调控机制。

The protein inhibitor of calcium-dependent proteases: purification from bovine heart and possible mechanisms of regulation.

作者信息

Mellgren R L, Carr T C

出版信息

Arch Biochem Biophys. 1983 Sep;225(2):779-86. doi: 10.1016/0003-9861(83)90089-9.

Abstract

A bovine heart protein which specifically inhibits calcium-dependent proteases has been purified to near homogeneity. The purified inhibitor had a Stokes radius of 6.8 nm estimated by gel filtration and a molecular weight of 145,000 estimated by sodium dodecyl sulfate-gel electrophoresis. There is evidence that it may be a glycoprotein. The inhibitor could be phosphorylated by bovine heart cyclic AMP-dependent protein kinase, and its inhibitory effect on Peak II (high-calcium-requiring) protease was modestly increased. However, no other phosphorylating or dephosphorylating conditions significantly influenced its activity. The inhibitor was not hydrolyzed by calcium-dependent proteases, but it was very sensitive to proteolytic inactivation by trypsin or proteases present in a lysosomal fraction from rat heart. Thus, proteolysis may represent a mechanism for decreasing the activity of the inhibitor in different physiologic or pathologic conditions.

摘要

一种能特异性抑制钙依赖性蛋白酶的牛心脏蛋白已被纯化至接近均一。通过凝胶过滤估计，纯化后的抑制剂斯托克斯半径为6.8纳米，通过十二烷基硫酸钠-凝胶电泳估计其分子量为145,000。有证据表明它可能是一种糖蛋白。该抑制剂可被牛心脏环磷酸腺苷依赖性蛋白激酶磷酸化，其对峰II（高钙需求）蛋白酶的抑制作用略有增强。然而，没有其他磷酸化或去磷酸化条件能显著影响其活性。该抑制剂不会被钙依赖性蛋白酶水解，但对胰蛋白酶或大鼠心脏溶酶体组分中的蛋白酶导致的蛋白水解失活非常敏感。因此，蛋白水解可能是在不同生理或病理条件下降低抑制剂活性的一种机制。