【摘要】 以胶体几丁质为诱导物,内生菌螺旋毛壳(Chaetomium spirale)ND35通过在SMCS液体培养基中振荡培养,获得了具几丁质酶活性的粗酶液。经硫酸铵沉淀、DEAE-Sepharose阴离子交换层析及Phenyl-Sepharose疏水层析,并通过SDS-PAGE鉴定,纯化了一种分子量约为42kDa的几丁质酶。其最适反应温度为40℃,在30℃以下很稳定；最适pH值为5．5,在pH 5-8．5范围内均较稳定；酶活性受Hg\+\{2+\}、Fe\+\{3+\}、Zn\+\{2+\}、Cu\+\{2+\}、Mg\+\{2+\}等金属离子不同程度的抑制,Na+对酶有轻微的激活作用；以胶体几丁质为底物时,该酶的米氏常数Km为1．72mg ml\+\{-1\},最大反应速度Vmax为21．18 Uml\+\{-1\}。更多还原

【Abstract】 The crude extract with chitinase activity induced by colloidal chitin was obtained from Chaetomium spir- ale ND35 in SMCS liquid medium.The chitinase was purified by ammonium sulfate precipitation,electrophoretic homogeneit and DEAE Sepharose Fast Flow anion-exchange chromatography,and Phenyl Sepharose Fast Flow hy- drophobic chromatography.Its molecular weight was ca.42 kDa analyzed by SDS-PAGE.The purified chitinase functioned optimally at 40℃and pH 5.5,and was stable within a broad range of pH 5-8.5 and below 30℃.The chitinase activity was inhibited by Hg²⁺,Fe³⁺,Zn²⁺,Cu²⁺ and Mg²⁺ and slightly stimulated by Na⁺.The K_m and V_max values for the chitinase,using colloidal chitin as substrate,were 1.72mg ml^-1 and 21.18 U ml^-1,respective- ly.更多还原