对嗜盐古菌Halogranum rubrum RO2-11所产胞外蛋白酶的特性进行初步研究，脱脂奶粉平板法验证其是否可以产生胞外蛋白酶，福林酚法测定胞外蛋白酶酶活。试验结果表明，嗜盐古菌Halogranum rubrum RO2-11可以产生胞外蛋白酶，此蛋白酶对高浓度的NaCl有一定的耐受性；酶促反应的最佳温度为50 ℃，在温度超过60 ℃后，对温度的耐受性下降；最佳pH为8.0，在pH 8.0~11.0之间有较高的活性并保持相对稳定，表明该酶是一种碱性蛋白酶；金属离子Ca2+对该蛋白酶有激活作用，Mn2+、Cu2+对该蛋白酶有抑制作用；金属螯合剂EDTA对蛋白酶有强烈的抑制作用，有机溶剂异丙醇、巯基反应物DTNB和丝氨酸抑制剂PMSF对酶活力的影响很小，表明该蛋白酶是一类不含巯基的金属蛋白酶，并且能够耐受一定浓度的有机溶剂。

In this study, the characteristics of an extracellular protease produced by Halogranum rubrum RO2-11 were studied. Skimmed milk powder medium was used to confirm extracellular protease production, while enzyme activity was determined by Folin-Phenol method. The results showed that Halogranum rubrum RO2-11 produced an extracellular protease with a certain tolerance to high concentration of NaCl. The optimum temperature for enzymatic reaction was 50 ℃. The temperature tolerance of the enzyme decreased at temperatures exceeding 60 ℃. The optimum pH for enzymatic reaction was 8.0. The enzyme showed high activity and stability between pH values of 8.0 and 11.0, demonstrating that the enzyme was an alkaline protease. The enzyme was activated by Ca2+ but was inhibited by Mn2+ and Cu2+. EDTA had a strong inhibitive effect on the protease. However, isopropanol, DTNB (a mercapto reactant) and PMSF (a serine inhibitor) had little influence on the activity of the enzyme, which showed that the enzyme might be a metalloprotease without a mercapto group and tolerant towards organic solvent to a certain extent.

国家自然科学基金（31340065）；江苏大学“青年骨干教师培养工程”；江苏高校优势学科建设工程资助项目