BT—37蛋白酶的初步研究

THE STUDY OF BT—37 PROTEASE

BT—37是从土壤中分离出的一株对多种鳞翅目昆虫有较高毒力的苏芸金芽孢杆菌。在PB培养基中振荡培养,蛋白酶活性随着细胞的生长而增强,培养36小时,芽孢晶体开始脱落时达到高峰。所产蛋白酶为中性蛋白酶。酶作用的最适条件:最适温度为50℃,60℃保温1.5小时酶活性降低70％;最适pH7.0;在pH6.0℃—10.6范围内稳定。1.5×10~3M时,Mn^+显著提高酶活。在蛋白酶活性高的培养基中获得了较高毒力的培养物。

The characteristics of the protease produced by BT--37, a Bacillus thuringiensis isolated from soil, were studied. Some characteristics were as follows: optimal pH 7.0, stable in the range of pH6.0—10.6; optimal temperature 50℃, about 70％ of its activity loss at 60℃ for 1.5hr. The protease was strongly inhibited by EDTA(1.5×10^(-3)M) and metal ion Mn could increase the activity by 37％. incubated on PB medium at 30℃. 250rpm for 36hr. When spore and crystal falled off, the peak of the enzyme producing was obtained. Higher toxicity production was obtained in the medium with higher protease activity.