Powar V K, Jagannathan V
J Bacteriol. 1982 Sep;151(3):1102-8. doi: 10.1128/jb.151.3.1102-1108.1982.
An enzyme which liberates Pi from myo-inositol hexaphosphate (phytic acid) was shown to be present in culture filtrates of Bacillus subtilis. It was purified until it was homogeneous by ultracentrifugation, but it still showed two isozymes on polyacrylamide gel electrophoresis. The enzyme differed from other previously known phytases in its metal requirement and in its specificity for phytate. It had a specific requirement for Ca2+ for its activity. The enzyme hydrolyzed only phytate and had no action on other phosphate esters tested. This B. subtilis phytase is the only known phytate-specific phosphatase. The products of hydrolysis of phytate by this enzyme were Pi and myo-inositol monophosphate. The enzyme showed optimum activity at pH 7.5. It was inhibited by Ba2+, Sr2+, Hg2+, Cd2+, and borate. Its activity was unaffected by urea, diisopropylfluorophosphate, arsenate, fluoride, mercaptoethanol, trypsin, papain, and elastase.
已证明枯草芽孢杆菌的培养滤液中存在一种能从肌醇六磷酸（植酸）释放无机磷酸盐（Pi）的酶。通过超速离心将其纯化至均一，但在聚丙烯酰胺凝胶电泳上仍显示出两种同工酶。该酶在金属需求和对植酸盐的特异性方面与其他先前已知的植酸酶不同。其活性对Ca2+有特定需求。该酶仅水解植酸盐，对所测试的其他磷酸酯无作用。这种枯草芽孢杆菌植酸酶是唯一已知的植酸盐特异性磷酸酶。该酶水解植酸盐的产物是Pi和肌醇单磷酸。该酶在pH 7.5时表现出最佳活性。它受到Ba2+、Sr2+、Hg2+、Cd2+和硼酸盐的抑制。其活性不受尿素、二异丙基氟磷酸酯、砷酸盐、氟化物、巯基乙醇、胰蛋白酶、木瓜蛋白酶和弹性蛋白酶的影响。
