| Título: | REGULATION OF EXPRESSION OF MULTIPLE BETA-GLUCOSIDASES OF ASPERGILLUS TERREUS AND THEIR PURIFICATION AND CHARACTERIZATION |
| Autores: |
Nazir, Asiya Soni, Rohit Saini, Harinder Manhas, Rajesh Kumari Chadha, Bhupinder |
| Fecha: | 2008-11-03 |
| Publicador: | Bioresources |
| Fuente: |
 |
| Tipo: |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
| Tema: | Aspergillus terreus, beta-glucosidases, multiplicity, differential expression, regulation, purification and characterization |
| Descripción: | This study reports the regulation and purification of -glucosidases from a thermotolerant Aspergillus terreus AN1 strain, previously reported for efficient deinking of composite paper waste. The differential expression of four -glucosidase isoforms, in response to carbon sources in production medium, was studied by electrophoretically resolving proteins by polyacrylamide gel electro-phoresis analysis (PAGE) and developing zymograms using methylum-belliferyl -D glucoside as substrate. Three -glucosidases (GI, GII & GIII) were purified using chromatographic techniques. SDS-PAGE revealed the respective molecular masses of GI, GII, and GIII, as 29, 43, and 98 KDa, and isoelectric point (pI) to be 2.8, 3.7, and 3.0. The -glucosidases exhibited diverse pH and temperature optima as well as stability. -Glucosidase I (GI) specifically recog-nized pNP--glucopyranoside (pNPG) as a substrate, whereas, -glucosidase II (GII) and III (GIII) also showed activities against cellobiose and salicin. In contrast to GII and GIII, the activity of GI was positively influenced in the presence of hexoses/pentoses and alcohols. Km and Vmax for hydrolysis of pNPG by GI, GII, andGIII were found to be 14.2 mM and 166.9 µmol -1mg protein -1, 4.37 mM, and 34.7 µmol -1mg proteins -1, and 11.1 mM and 378.7µ mol -1 mg protein -1, respectively. |
| Idioma: | Inglés |