β- D-glycosidase activities of Humicola grisea: biochemical and kinetic characterization of a multifunctional enzyme

• Published in: Biochimica et biophysica acta Vol. 1033; no. 3; pp. 243 - 249
• Main Authors: Peralta, Rosane Marina, Terenzi, Héctor Francisco, Jorge, João Atilio
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 26.03.1990; Elsevier; North-Holland
• Subjects: actine site; alpha-L-Fucosidase; alpha-L-Fucosidase - metabolism; analysis; beta-galactosidase; beta-Galactosidase - metabolism; beta-glucosidase; beta-Glucosidase - metabolism; Biological and medical sciences; Cellobiase; cellobiose; Chromatography, Gel; Electrophoresis, Polyacrylamide Gel; enzyme activity; Enzyme kinetics; enzymology; Fundamental and applied biological sciences. Psychology; Glycoside Hydrolases; Glycoside Hydrolases - analysis; Glycoside Hydrolases - isolation & purification; Glycoside Hydrolases - metabolism; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; H. grisea; Humicola; Hydrogen-Ion Concentration; Hydrolysis; isolation; isolation & purification; Kinetics; Lactase; metabolism; Microbiology; Mitosporic Fungi; Mitosporic Fungi - enzymology; Molecular Weight; Mycology; physicochemical properties; Protein Denaturation; Substrate Specificity; Temperature; β-Fucosidase; β-Galactosidase; β-Glucosidase; PNP-Fuc; β-Glucosidase; ONPG; Lactase; Cellobiase; PNP-Glc; β-Fucosidase; Enzyme kinetics; H. grisea; β-Galactosidase; PNP-Gal; Fungi; Purification; Enzymatic activity; Enzyme; Active site; Substrate specificity; Glycosidase; Fungi Imperfecti; Kinetics; Humicola; Physicochemical properties; Thallophyta
• ISSN: 0304-4165; 0006-3002; 1872-8006; 1878-2434
• DOI: 10.1016/0304-4165(90)90127-I

A β- d-glycosidase activity was purified from mycelium of Humicola grisea var. thermoidea grown on avicel as the main carbon source. The purified enzyme was a glycoprotein and migrated as a single polypeptide band on polyacrylamide gel electrophoresis under native or denaturing conditions. The apparent molecular weight of the enzyme was estimated to be 55 kDa by gel filtration and SDS-PAGE. The enzyme was active against o-nitrophenyl β- d-galactoside; p-nitrophenyl β- d-glucoside, p-nitrophenyl, lactose and celloboise, PNP fucoside (synthetic substrate)_and celloboise (natural substrate) being the best utilized. A comparison of the properties of β- D-galactosidase, β- d-glucosidase and β- d-fucosidase showed that three activities axhibited similar pH and temperature optima and the same thermostability. The hydrolysis rate of substrate mixtures suggests that the enzyme possesse a common catalytic site for all the substrates assayed.