【摘要】 利用硫酸铵分级沉淀和交联葡聚糖G-100凝胶柱纯化了高效降解羽毛的嗜麦芽窄食单胞菌YHYJ-1所产角蛋白酶,纯化的角蛋白酶,经SDS-PAGE蛋白电泳分析,分子量为48.3 kda。结果表明,该酶最适反应温度和最适pH值分别为50℃和9.0,30～40℃具有较好的温度稳定性,60℃酶活下降很快;在pH 7.0～9.5的范围内具有较好的稳定性。金属离子Ni2+、Zn2+对角蛋白酶具有明显抑制作用,Cu2+、Fe2+、Fe3+能完全抑制酶活;1%巯基乙醇对酶具有明显激活作用。EDTA和PMSF对该角蛋白酶几乎完全抑制,可判定该酶是丝氨酸金属蛋白酶,是一种新的蛋白酶。更多还原

【Abstract】 A keratinase secreted by a feather-degrading Stenotrophomonas maltophilia strain YHYJ-1 cultivated in medium containing chicken feather meal was purified by ammonium sulphate precipitation and Sephadex G-100 chromatographic.The molecular mass of the purified enzyme was estimated to be 48.3kDa by sodium dodecyl sulfate(SDS) polyacrylamide gel electrophoresis.The result showed that the optimum pH and temperature for the purified keratinase were 9.0 and 50 °C,respectively.The keratinase was stable at pH7.0 and 9.5 ℃ or 30-40 ℃,and its activity decreased rapidly at 60 ℃.The enzyme was inhibited by Ni2+ and Zn2+,wholly inhibited by Cu2+,Fe2+ and Fe3+,and stimulated by β-mercaptoethanol.The keratinase was wholly inhibited by EDTA and PMSF,which was considered to be a novel serine metallokeratinase.更多还原