丁鳜肠道中枯草芽孢杆菌蛋白酶的生理生化性质的研究

Physiologic and Biochemical Character of the Protease Produced by Bacillus subtilis from Intestine of Tinca tinca L.

目的：为改良丁鳜饲料成分,研究了从丁鳜肠道中分离的枯草芽孢杆菌（Bacillus subtilis）蛋白酶的生理生化性质。方法及结果：枯草芽孢杆菌经发酵培养,破碎细胞,通过45%-85%饱和度的硫酸铵沉淀分离得到了一种碱性蛋白酶,SDS-PAGE显示该蛋白酶分子量为59kD;最适温度为40℃;温度的稳定性范围在50℃以下;最适pH9.8。低浓度的EDTA对该酶无明显抑制作用;Ca^2＋和Co^2＋完全抑制该酶的活性,Pb^2＋对酶活力有一定抑制作用。结论：新分离出的这种蛋白酶有助于进一步开发含有添加蛋白酶制剂的鱼饲料。

Objective：To improve feedstuff＇s ingredients of Tinca tinca, the physiological and chemical property of protease, which was produced by Bacillus subtilis separated from intestine of the fish were determined. Method and result： after culture of Bacillus subtilis in fermentation medium, staved the cells, a kind of alkaline protease was got by （NH4）2SO4 precipitation with saturation 45% - 85%. The protease temperature optimum and temperature stability is 40℃ and under 50℃ respectively, and the optimum pH was 9.8. The molecular weight of protease was 59kD measured by SDS - PAGE. Low concentration EI）TA hadn＇ t effect on the protease activity, Ca^2＋ and Co^2＋ almost inhibited the protease activity, however, Pb2~ could partly inhibit the protease activity. Conclusion： This newly separated protease help develop feedstuff for fish, which contain protease as a kind of ingredient.