【摘要】 嗜热芽孢杆菌XJT—9503菌的发酵液经硫酸铵和丙酮分级沉淀分离纯化得到聚丙烯酰胺凝胶电泳均一的高温中性蛋白酶制品。SDS—PAGE测得酶分子量为3000。当以酪蛋白为底物时，酶反应最适温度为65℃，最适pH为7．在PH6．5—9范围内稳定。在65℃、0、02MpH7．5的磷酸缓冲液中的半衰期为54min。金属离子铜、汞、铝强烈抑制酶活，钙离子，镁离子对酶活有促进作用。更多还原

【Abstract】 Thermophilic Bacillus XJT-9503 liquid bacterial culture is pre-treatmented with 1 %CaCl2, 1 % Na2HPO4 and kept at 65℃ for 15 minutes, 10000r/m, centrifugated for 15 min-inutes.Collect the supernatant and fractional precipitate it by amononium sulfate, acetone，al- ternatively. After this treatment, we get the pure thermodurc neutral proteinase whose puri-ty is identified by SDS-PAGE. Properties of the pure enzyme has been studied. Its MW isabout 30000, Optimum reaction temperature is 65℃. Optimum reaction pH is 7, Its half-life period at 65℃, in 0. 02M pH7. 5 phosphate buffer is 54 minutes, ’Al3+, Hg’2+ inhibit itsactivily, to the contrazy, Ca(2+), Mg(2+) can improve its activity.更多还原