来自牛红细胞的泛素的对硝基苯磷酸酶活性。

The p-nitrophenyl phosphatase activity of ubiquitin from bovine erythrocytes.

作者信息

Taniguchi N, Matsumoto H

出版信息

Comp Biochem Physiol B. 1985;81(3):587-90. doi: 10.1016/0305-0491(85)90371-2.

Abstract

Ubiquitin, a unique protein with esterase and carbonic anhydrase activity, has been found to have also a p-nitrophenyl phosphatase activity. This phosphomonoesterase activity of ubiquitin has an acidic pH optimum; its true substrate appears to be the phosphomonoanion, with a Km of 1.8 X 10(-3) M. It is competitively inhibited by the typical acid phosphatase inhibitors, arsenate (Ki = 1.3 X 10(-3) M), molybdate (Ki = 1.2 X 10(-6) M), and phosphate (Ki = 1.4 X 10(-3) M). These inhibitors have no effect on the CO2 hydration and p-nitrophenyl acetate esterase activities of the ubiquitin. Acetazolamide slightly inhibited the p-nitrophenyl phosphatase activity.

摘要

泛素是一种具有酯酶和碳酸酐酶活性的独特蛋白质，现已发现它还具有对硝基苯磷酸酶活性。泛素的这种磷酸单酯酶活性在酸性pH条件下最适宜；其真正的底物似乎是磷酸单阴离子，米氏常数为1.8×10⁻³M。它受到典型酸性磷酸酶抑制剂砷酸盐（抑制常数Ki = 1.3×10⁻³M）、钼酸盐（Ki = 1.2×10⁻⁶M）和磷酸盐（Ki = 1.4×10⁻³M）的竞争性抑制。这些抑制剂对泛素的二氧化碳水合活性和对硝基苯乙酸酯酶活性没有影响。乙酰唑胺对硝基苯磷酸酶活性有轻微抑制作用。