球形芽孢杆菌C_3—41菌株胞外蛋白酶特性

球形芽孢杆菌能够合成具杀蚊活性的蛋白晶体,该晶体在蚊中肠碱性条件下降解产生毒性,尽管球形芽孢杆菌蛋白酶与杀蚊毒素的降解无关,但它在球形芽孢杆菌杀蚊制剂的产生中有重要意义。同时球形芽孢杆菌产生的碱性蛋白酶具有潜在的医疗价值。 我们以本实验室分离的高效杀蚊菌C_3—41菌株为材料,研究了球形芽孢杆菌蛋白酶的产生特性及其理化性质,在国内尚属首次报道。

THE PROPERTIES OF PROTEASE FROM BACILLUS SPHAERICUS C_3-41

The production and properties of protease from Bacillus sphaericus strain C3-41 were reported in this paper. It was found out that the secrete of extracellular protease began at the exponential phase, reached a maximum at the early phase of sporangium and then decrease rapidly. The production conditions of the protease have been studied. The protease preparation was purified by salting out with ammonium sulfate and by chromatography fractionating on Sephadex G-100. The purified enzyme have a specific activity of 6741.5 U/mg protein and a molecular weight of 42,000. The optimal activities of the protease were around pH11.0 and at 4 degrees C respectively. The enzyme was stable at pH5.0-12.0. The proteolytic activity was inhibited by phenylmethylsulphony fluoride (PMSF) and EDTA, but not by IAA, SA and DTT. The activity was inhibited in the presence of Al3+, Hg2+, Fe3+, Cu2+ and Fe2+. The enzyme was sensitive to higher temperature, but was quite stable in the presence of Ca2+.