Kuno T, Matsuda Y, Katunuma N
Biochem Int. 1984 Apr;8(4):581-8.
Previously it was found that the proteolytic processing of precursors of gamma-glutamyltranspeptidase takes place on the brush border membrane of the kidney. The activity of the processing protease in purified brush border membranes was examined using endogenous substrates labeled with [3H]fucose and [35S]methionine. On incubation with brush border membranes in vitro, the precursors were converted stoichiometrically to two subunits, and the reaction followed first order kinetics with a rate constant k of -0.048 min-1. The enzyme responsible for this conversion was membrane-bound, had a weakly basic optimum pH and was inhibited by serine protease inhibitors. These results suggest that the precursor of gamma-glutamyltranspeptidase is processed to the mature form by a serine protease bound to the brush border membrane of kidney.
此前发现，γ-谷氨酰转肽酶前体的蛋白水解加工发生在肾脏的刷状缘膜上。使用用[3H]岩藻糖和[35S]甲硫氨酸标记的内源性底物，检测了纯化的刷状缘膜中加工蛋白酶的活性。在体外与刷状缘膜一起孵育时，前体化学计量地转化为两个亚基，反应遵循一级动力学，速率常数k为-0.048 min-1。负责这种转化的酶是膜结合的，具有弱碱性的最适pH值，并被丝氨酸蛋白酶抑制剂抑制。这些结果表明，γ-谷氨酰转肽酶前体被肾脏刷状缘膜结合的丝氨酸蛋白酶加工成成熟形式。
