Purification and properties of three cellobiases from Aspergillus niger A20

• Published in: Applied biochemistry and biotechnology Vol. 76; no. 1; pp. 33 - 44
• Main Authors: Abdel-Naby, M.A, Osman, M.Y, Abdel-Fattah, A.F
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 1999; Springer Nature B.V
• Subjects: amino acids; Amino Acids - metabolism; Aspergillus niger; Aspergillus niger - enzymology; Aspergillus niger - metabolism; beta-Glucosidase - isolation & purification; beta-Glucosidase - metabolism; Biochemistry; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Carbohydrate Metabolism; Chromatography, DEAE-Cellulose; Chromatography, Gel; Electrophoresis, Disc; enzyme activity; Enzymes; Fundamental and applied biological sciences. Psychology; Fungi; heat stability; Hydrogen-Ion Concentration; Kinetics; metal ions; Miscellaneous; Mission oriented research; O-glycoside hydrolases; purification; Studies; substrates; sugars; Temperature; Transferases - metabolism; Ultrafiltration; Fungi; β-Glucosidase; Purification; Enzyme; Aspergillus niger; Glycosidases; Hydrolases; Fungi Imperfecti; Kinetic parameter; O-Glycosidases; Physicochemical properties; Thallophyta
• ISSN: 0273-2289; 1559-0291; 0273-2289
• DOI: 10.1385/ABAB:76:1:33

Three cellobiases, here called cellobiase A, B, and C, from the culture filtrate of Aspergillus niger A20, were purified by precipitation with ammonium sulphate, gel filtration through Sephadex G-75, and column chromatography of DEAF-cellulose. The purified enzymes were homogeneous on polyacrylamide disk electrophoresis. The mol wt of the purified enzymes were estimated by SDS-gel electrophoresis to be 88,000, 80,000, and 71,000 for cellobiases A, B, and C, respectively. The enzymes were active at pH 4.5 and 55-60 degrees C. The pattern of their amino acid compositions showed high contents of aspartic acid, glutamic acid, threonine, serine, and glycine. The apparent Km values for cellobiose were 0.9, 1.63, and 1.0 mM for cellobiases A, B, and C, respectively. Calcium ions stimulated cellobiases B and C, and Co2+ and Mg2+ ions stimulated cellobiase A. The purified enzymes hydrolyzed cellobiose and aryl-beta-D-glucosides, but they had no action on sucrose, maltose, and cellulose. The three cellobiases catalyzed transglycosylase reaction, and the major product formed from cellobiose was tetramer of glucose.