蜂房哈夫尼菌胞外蛋白酶的特性

Characterization of extracellular protease from Hafnia alvei

从即食海参中分离到一株条件性致病菌—蜂房哈夫尼菌(Hafnia alvei H4),对该菌所产胞外蛋白酶进行了初步研究。结果表明,菌株生长达到对数期时检测到最大酶活力,硫酸铵质量分数为50%时提取的胞外蛋白酶活力最大,该菌所产胞外蛋白酶的最适反应条件为45℃、pH 7.5、0.5%NaCl;Cu^2+、Zn^2+、Fe^2+对胞外蛋白酶活力具有抑制作用,而Ca^2+、Mn^2+对胞外蛋白酶活力具有促进作用。丝氨酸蛋白酶抑制剂PMSF对胞外蛋白酶的活性具有抑制作用,说明该胞外蛋白酶主要是丝氨酸蛋白酶。红外光谱图显示蛋白酶在1663 cm^-1处有吸收峰,表明其具有高级结构。

A conditional pathogen,Hafnia alvei H4,was isolated from spoiled instant sea cucumber.The extracellular protease produced by Hafnia alvei H4 was studied.The result showed that the maximum enzyme activity was detected when the bacterial growth reached logarithmic phase,which was obtained when the ammonium sulfate content was 50%.The optimal reaction conditions of extracellular protease were 45℃,pH 7.5,0.5%NaCl;Cu^2+,Zn^2+and Fe^2+inhibited the activity of extracellular protease,while Ca^2+and Mn^2+promoted the activity of extracellular protease.PMSF,a serine protease inhibitor,inhibited the activity of extracellular protease,indicating that the extracellular protease were serine proteases.The infrared spectrum shows that the protease had an absorption peak at 1663 cm^-1,indicating that it has a high-level structure.