title: Purification and properties of an endoglucanase of Aspergillus terreus DSM 826.
abstract: Endoglucanase (EG) from A. terreus DSM 826 grown on sugar cane bagasse as a carbon source was purified using acetone fractionation, then a Sepharose-4B chromatographic column, with purification of about 27-fold and 10.5% recovery. The optimum temperature and pH for activity of the purified EG were found to be 50 degrees C and pH 4.8, respectively. The purified enzyme can stand heating up to 50 degrees C for 1 h without apparent loss of activity. However, the enzyme, incubated at 80 degrees C for 5 min, showed about 56% loss of activity. Optimum EG activity was recorded with a citrate buffer system (pH 4.8; 0.05 M). Co2+ (2.5 x 10(-2) M) and Zn2+ (5 x 10(-2) M) were found to activate the purified EG of A. terreus DSM 826 by about 83 and 25%, respectively. On the other hand, Hg2+ inhibited the activity of the purified EG by about 50 and 71% at a concentration of 2.5 x 10(-2) and 5 x 10(-2) M, respectively. Carboxymethyl cellulose was found to be the best substrate for the purified EG, with V(max) values of 4.35 micrpmol min(-1) mg(-1) protein.
authors.affiliation: Department of Microbial Chemistry, National Research Center, Dokki, Cairo, Egypt. alielshafei@yahoo.com
authors.forename: Ali M
authors.initials: AM
authors.lastname: Elshafei
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Hassan
authors.forename: Bakry M
authors.initials: BM
authors.lastname: Haroun
authors.forename: Osama M
authors.initials: OM
authors.lastname: Abdel-Fatah
authors.forename: Housam M
authors.initials: HM
authors.lastname: Atta
authors.forename: Abdelmageed M
authors.initials: AM
authors.lastname: Othman
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism; D002480:Cellulase / Q000302:isolation & purification* / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D002847:Chromatography, Agarose; D002951:Citrates; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D016014:Linear Models; D008670:Metals; D012685:Sepharose; D000077559:Sodium Citrate; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002951:Citrates; D005656:Fungal Proteins; D008670:Metals; D000077559:Sodium Citrate; D002482:Cellulose; C027433:bagasse; D012685:Sepharose; D002480:Cellulase; D002266:Carboxymethylcellulose Sodium