一株产低温蛋白酶菌株的筛选鉴定及纯酶研究

Characterization of a strain producing cold-adapted protease and enzyme purification.

从土壤中分离筛选获得一株产低温蛋白酶菌株，并对其进行了形态和生理生化鉴定，对部分长度的16S rDNA同源性作了分析，将其鉴定为Chryseobacterium sp．HL221，通过硫酸铵沉淀、G-75和DEAE Sepharose F．F．柱层析从发酵液分离纯化得到纯酶，测得分子量为35000Da，等电点为4．9．酶促反应最适温度25℃，最适pH为7，酶活在低于25℃，pH7～10范围内稳定．

A strain producing cold-adapted protease was isolated from soil and identified, named strain HL221. It was suggested that strain HL221 was the closest relative of Chryseobacterium scophthalmum, based on phylogenetic analysis of 16S rDNA with 990//00 of sequence identity, morphological, cultural and physiological characteristics of strain. The PAGE homogenous protease was purified with 27 folds and recovery rate of 16 % by （NH4）2SO4 fractionation, gel filtration on Sephadex G-75 and DEAE Sepharose Fast Flow. The molecular weight of the enzyme was determined to be 35000 Da by SDS-PAGE, its isoelectric point pI4.9 was determined by PAGE-IEF. The enzyme activity was optimal at pH7 with 25℃. The enzyme was stable over the range of pH 7-10 with below 25 ℃.