粘质赛氏菌胞外蛋白酶的提取、纯化及部分性质研究

经过硫酸铵３０％～５０％分级沉淀、二步柱层析可获聚丙烯酰胺凝胶电泳均一的粘质赛氏菌胞外蛋白酶制品，收率可达５３％，并制备了酶的结晶，该酶以ＳｅｐｈａｄｅｘＧ１００柱层析及ＳＤＳ－ＰＡＧＥ测得分子量约为８１０００，该酶的最适ｐＨ为７．０，最适温度为４５℃，Ｚｎ２＋、Ｍｎ２＋、Ｆｅ２＋、Ｃｕ２＋、Ｃｏ２＋等重金属离子不同程度地抑制酶活性。

Purification and Characterization of a Proteinase from Serratia Marcescens

The extracellular proteinase from Serralia Marcescens 41003(2) has been purified by a series methods including:(NH4)2SO4 fractional salting out(30%-50%),Sephadex G-100 chromatography and DEAE-Cellulose 32 chromatography.The purified proteinase was about 46-fold purity of the culture supernatant by enzyme assay.It was found to be hornogeneous as judged by PAGE.The purified proteinase showes approximate molecular weight of 81 000 by Sephadex G-100 chromatography.The proteinase exhibits an optimum pH about 7.0 for casein digestion and optimum temperature at 45℃.Its activity is stable below 45℃.and can be inhibited by Zn2+.Mn2+,Fe2+,Cu2+ and Co2+.The rod shape crystalls of the proteinase have been obtained from ammonium sulfate solution.