中文摘要：

从中度嗜盐菌Salinivibrio sp.YH4发酵的粗酶液中分离纯化出蛋白酶EYHⅠ,对其进行酶学性质分析、串联质谱鉴定及全基因克隆。结果表明,EYHⅠ属于金属蛋白酶,最适温度55℃,热稳定性较好。最适p H为9.0,碱性条件下较稳定;在4 mol/L的Na Cl溶液中EYHⅠ仍保持较高活性,EYHⅠ全基因序列共1 836 bp,蛋白序列共611个氨基酸。比对发现EYHⅠ氨基酸序列与Salinivibrio sp.AF-2004所产Zn金属蛋白酶前体(ABI93183)同源性最高(96%)。结构分析表明,EYHⅠ由一个FTP结构域,一个Pep SY结构域,一个M4中性蛋白酶和一个PPC结构域组成。本研究为嗜盐菌及其胞外蛋白酶的生产和应用奠定了理论基础。

英文摘要：

The extracellular proteases from moderate halophilic strain,Salinivibrio sp.YH4 was isolated,purified, identified and characterized to provide data for enzyme system of Salinivibrio sp..Strain was cultured in liquid fermen-tation medium,the extracellular proteases was purified by using HiTrap Capto DEAE column chromatography and Gel filtration chromatography.The protease was identified by using mass spectrometry (MS)and designated as EYHⅠ. The metalloprotease EYHⅠ had optimal activity at 55 ℃ and pH 9. 0,stabilized at 60℃ and pH 7. 0~1 1. 0.EYHⅠshowed higher proteolytic activity at 4 mol/L NaCl.The nucleotide sequence contains 1836 bp,encoding EYHⅠof 611 amino acid residues,which is highly conserved to zinc metalloprotease precursor in Salinivibrio sp.AF-2004 with 96%sequence similarity.Analysis of the structure showed that EYHⅠcontained an FTP domain,a PepSY domain,M4 neu-tral protease and a PPC domain.These results may provide important data for the study of Salinivibrio sp.and the appli-cation of protease EYHⅠ.