特异腐质霉纤维素酶的分离纯化与性质

Purification and Characterization of Cellulases from Humicola insolens

特异腐质霉Humicola insolens（YH-8）能高效合成高稳定性的纤维素酶。由该菌株所产的纤维素酶粗液经过1．5倍酒精沉淀、DEAE-SephadexA-50离子交换层析，SephadexG-100凝胶过滤，得到电泳纯的纤维素酶组分一个。对这个组分的催化性质（以羧甲基纤维素为底物）进行了研究，该酶的最适催化温度60℃，pH值为5．5，在50℃以下酶的稳定性较好，70℃条件下底物对酶有较强的保护作用，该酶的pH稳定性范围为4～8，Zn^2＋，Ca^2＋，Mg^2＋，K^＋，Li^＋对酶活有促进作用，Mn^2＋、Co^2＋、Fe^2＋、Fe^3＋对酶活起抑制作用，酶对CMC-Na和水杨素有分解作用，而不分解脱脂棉和滤纸。

The cellulases from Humicola insolens, which has high ability to synthesze high stability cellulases, were purified by means of 1.5 folds volume ethanol deposition, DEAE-SephadexA-50 chromatography and SephadexG-100 chromatography. The purified cellulase showed a single band on SDS-polyacrylamide gel electrophoresis （PAGE）. The biocatalyzed characters of the purified cellulase were investigated with the CMC-Na as substrate. The most appropriate cata- lyzed temprature and pH for it is 60℃ and 5.5 respectively. It has the extreme stability at the temperatures no more than 50 ℃. The CMC-Na has the protective effect on the cellulase. The pH stability range of the purified cellulase is 4～8,Zn^2＋,Ca^2＋,Mg^2＋,K^＋,Li^＋ can ativate the cellulase. And cellulase can mainly decompose CMC and salicin, but can decompose other substrates feebly.