顶青霉D_(15)木聚糖酶提纯及性质研究

PURIFICATION AND CHARACTERIZATION OF FOUR XYLANASES FROM PENICILLIUM CORYLOPHILUMD_(15)

经硫酸铵分级沉淀,BiO-gelP60凝胶过滤,和DEAE离子交换层析,从顶青霉D_15的麦麸培养物中提纯,得到4个具有凝胶电泳纯的木聚糖酶组分D_(x1)、D_(x2)、2_(x3)、D_(x4)、SDS—凝胶电泳法测得各个组分的分子量是:D_(x1),76000;D_(x2),4300;D_(x3),32500;D_(x4),29500。圆盘等电聚焦电泳法测得4个组分的等电点分别为4.50、5.70、5.30和5.20。热处理60分钟,D_(x1)、D_(x2),D_(x3)、D_(x4)的半失活温度分别为51.7℃、50.8℃、54.6℃和55.6℃。D_(x1)、D_(x4)在pH3.6—6.6稳定,D_(x2)和D_(x3)则在pH2.4—6.0稳定。各组分的A_(280)(1cm(?)mg/m1)分别是:D_(x1),0.97;D_(x2),1.46;D_(x3),0.98和D_(x4),1.07。

Four xylanases, D_(x1), D_(x2), D_(x3), and D_(x4), have been purified from Penicillium corylophilum D_(15) by (NH_4)_2SO_4 fractionation, gel filtration on Bio-gel P60, ion exchange on DEAE—cellulose and DEAE—Sephadex A_(25). The xylanases were shown to be homogeneous by the criteria of polyacrylamide gel electrophoresis. The molecular weights were estimated to be 76000,43000,32500 and 29500,with pI value, s of 4.50,5.70,5.30 and 5.20,respectively. D_(x19),D_(x4) were stable in the pH range of 3.6—6.6, D_(x2) and D_(x3) were stable in pH2.4—6.0. The temperature for the loss of half activity within 60 minutes were 51.7℃ for D_(x1), 50.8℃ for D_(x2), 54.6℃ for D_(x3) and 55.6℃ for D_(x4). The A_(280) (1cm.mg/ml) of the xylanases were determined to be 0.97, 1.46, 0.98 and 1.07, respectively.