A highly thermostable β-glucosidase activity from the thermophilic fungus Humicola grisea var. thermoidea: purification and biochemical characterization
- 作者：Peralta ; Rosane Marina ; Kadowaki ; Marina Kimiko ; Terenzi ; Hé ; ctor Francisco ; Jorge ; Joã ; o Atilio
- 关键词：β ; -Glucosidase ; β ; -Xylosidase ; Cellobiase ; Xylosidase ; CM-case ; Humicola grisea
- 刊名：FEMS Microbiology Letters
- 出版年：1997
- 期刊代码：34_03781097
- 类别：imm
- 出版时间：January 15, 1997
- 卷：146
- 期：2
- 页码：291-295
- 文件大小：403 K
摘要
Humicola grisea var. thermoidea grown in sugar cane bagasse produced and secreted two major protein components exhibiting β-d-glycosidase activities (forms I and II). Form I was purified to apparent homogeneity (PAGE and SDS-PAGE) by a three-step procedure involving acetone precipitation, DEAE-cellulose chromatography and filtration in Bio-Gel P-100. The purified enzyme was a glycoprotein of 35%carbohydrate content and apparent molecular mass of 55 kDa (SDS-PAGE and gel filtration), Optima of temperature and pH were 50-60°C and 6.0, respectively. The enzyme activity was stable at 60°C and exhibited a half-life of 30 min at 70°C. The enzyme hydrolyzed p-nitrophenyl β-d-glucopyranoside, cellobiose, xylobiose,p -nitrophenyl β-d-xylopyranoside and CM-cellulose. Kinetic studies indicated that these substrates were hydrolyzed at the same catalytic site.