嗜热脂肪芽孢杆菌HY－69耐热中性蛋白酶的性质研究  

Studies on Properties of an Extracellular Thermostable Neutral Protease from Bacillus stearothermophilus HY-69

作　　者：金城[1] 杨寿钧[1] 张树政[1] 

机构地区：[1]中国科学院微生物研究所

出　　处：《生物化学与生物物理学报》1994年第4期357-363,共7页

基　　金：国家自然科学基金

摘　　要：嗜热脂肪芽孢杆菌ＨＹ－６９的耐热中性蛋白酶已纯化。研究了纯酶的性质；该酶分子量为２４ｋｄ，由６个单体构成一个六聚体。酶的等电点９．１５．最适作用ｐＨ为７．５，最适作用温度为８５℃：该酶具有很好的耐热性，９０℃时酶活半寿期为２２ｍｉｎ，８０℃保温３小时，酶活仍保持６３％；酶的ｐＨ稳定性也很好。该酶是金属蛋白酶，活性中心含锌离子，酶的热稳定性依赖于钙离子。测定了酶的氨基酸组成和Ｎ末端氨基酸序列。An extracellular thermostable neutral protease had been purified. It had a molecular weight of approx. 24kd, an isoelectric point of about 9.15, an optimum pH of 7.5 and an optimum temperature of 85℃.The protease consists of six subunits(24kd).It exhibited a very high degree of thermostability(the half-life time at 90℃ was 22min) which was showed to be dependent on the presence of Ca2+. It was stable within a wide ranges of pH at various temperatures (40℃, pH6.0-12.0;70℃,pH6.0-10.0;80℃,pH 6.0-8.0).The protease was sensitive to metal-chelator. Zinc was necessary to the activity.The amino acid composition and N-terminal sequence of the protease had been determined.

关 键 词：嗜热 脂肪 芽孢杆菌 蛋白酶 耐热性 

分 类 号：Q939.110.6[生物学—微生物学]