对液体发酵的棒曲霉Asp-195v菌株所产蛋白酶的活力进行了研究,并通过分离纯化获得了电泳纯的酶蛋白。研究结果表明,该蛋白酶的最适反应温度为40℃,在30-50℃温度范围内相对活力可保持在70%以上;最适pH为7,pH稳定范围在4-8;Mn2+对该蛋白酶活力有明显的激活作用,K^+、Ag^+、Cu^2+、Fe^2+、Mg^2+、Zn^2+、Ca^2+、Al^3+和Fe^3+离子则有明显的抑制作用,尤其是Hg2+和Pb2+对酶活的抑制作用更加强烈;其他试剂如葡萄糖、EDTA对酶活的抑制作用不明显,而蔗糖、SDS和Tween-20对酶活的抑制明显;以酪氨酸为底物采用双倒数作图法测得Vmax为30.40mmol/min,Km为97.53mmol/L。该酶的表观分子量为30.1kDa。
The fermenting liquor from Aspergillus clavatus Asp-195v screened for high protease production was purified in order to obtain the protease protein. The test of the enzyme characteristics showed that the optimum temperature for enzyme activity was 40℃ , and the activity remained more than 70% in 30-50 ℃. The activity remained stable in the range of pH 4-9 with the optimum requirement of pH 7. Mn2+ had an obvious activation on the protease activity. The protease activity was obviously inhibited by K^+, Ag^+, Cu^2+, Fe^2+, Mg^2+, Zn^2+, Ca^2+, Al^3+ and Fe^3+, and severely inhibited by Hg2+ and Pb2+. Other reagents such as glucose and EDTA make little inhibition to the enzyme, on the contrary the sucrose, SDS and Tween-20 have an obvious inhibiting effect. Vmax, Km and molecular weight of the enzyme were 30.40mmol/min, 97.53mmol/L and 30.1kDa respectively.