Allam A M, Hussein A M, Ragab A M
Z Allg Mikrobiol. 1975;15(6):393-8. doi: 10.1002/jobm.3630150602.
alpha-Amylase of the thermophilic actinomycete Thermomonospora vulgaris was partially purified. Maximal enzyme activity was obtained at 60degreeC and pH 6.0. KM value was l.4%. The effect of some metal salts on enzyme activity was studied. Enzyme activity was inhibited by by KCN, EDTA, and iodoacetate. Inhibition by EDTA was completely nullified by CaCl2, but the inhibition by iodoacetate was not overcome by 2-mercaptoethanol. Exposure of the enzyme to pH 7.0 and 9.0 for 2 hr. did not affect the enzyme, but exposure to pH 3.0 for few minutes completely inactivated the enzyme. Exposure of the enzyme to 60degreeC resulted in an appreciable inactivation and exposure to 80degreeC completely inactivated the enzyme. Addition of CaCl2, 2-mercaptoethanol, or enzyme substrate the 60degreeC exposed enzyme. However, bovine serym albumin had a protective effect when the enzyme was exposed to 60degreeC but not to 80degreeC. The enzyme was stable in the presence of 8 M urea.
嗜热放线菌普通嗜热单孢菌的α淀粉酶得到了部分纯化。在60℃和pH 6.0条件下获得最大酶活性。米氏常数为1.4%。研究了一些金属盐对酶活性的影响。酶活性受到KCN、EDTA和碘乙酸的抑制。EDTA的抑制作用可被CaCl2完全消除，但碘乙酸的抑制作用不能被2-巯基乙醇克服。将酶暴露于pH 7.0和9.0环境2小时，对酶没有影响，但暴露于pH 3.0几分钟会使酶完全失活。将酶暴露于60℃会导致明显失活，暴露于80℃会使酶完全失活。向60℃暴露的酶中添加CaCl2、2-巯基乙醇或酶底物。然而，当酶暴露于60℃而非80℃时，牛血清白蛋白具有保护作用。该酶在8 M尿素存在下稳定。
