No abstract

1994. Production, purification, and characterization of an extracellular endo-a-l,3-glucanase from a monokaryon of Schizophyllum commune ATCC 38548 defective in exo-P-1,3-glucanase formation. Can. J. Microbiol. 40: 18-23. Production of extracellular P-1,3-glucanase activity by a monokaryotic Schizophyllum commrtne strain was monitored and results indicated that the P-glucanase activity consisted of an endo-P-l,3-glucanase activity, besides a negligible amount of P-1,6-glucanase and P-glucosidase activity. Unlike the P-I ,3-glucanase production of the dikaryotic parent strain S. commune ATCC 38548, the P-1.3-glucanase formation of the monokaryon was not regulated by catabolite repression. The endo-P-I ,3-glucanase of the monokaryon was purified from the culture filtrate by lyophilization, anion exchange chromatography on Mono Q, and gel filtration on Sephacryl S-100. It appeared homogeneous on SDS-PAGE with a molecular mass of 35.5 kDa and the isoelectric point was 3.95. The enzyme was only active toward glucans containing P-1,3-linkages, including lichenan, a P-1 ,3-1,4-D-glucan. It attacked laminarin in an endo-like fashion to form laminaribiose, laminaritriose, and high oligosaccharides. While the extracellular P-glucanases from the dikaryotic S. commune ATCC 38548 degraded significant amounts of schizophyllan, the endo-P-l,3-glucanase from the monokaryon showed greatly reduced activity toward this high molecular mass fi-1,3-/P-1,6-glucan. The K, of the endoglucanase, using laminarin as substrate, was 0.28 mg/mL. Optimal pH and temperature were 5.5 and 50°C, respectively. The enzyme was stable between pH 5.5 and 7.0 and at temperatures below 50°C. The enzyme was completely inhibited by 1 mM H~~+ .Growth of the monokaryotic S. commune strain was not affected by its constitutive endo-P-l,3-glucanase formation. . 1994. Production, purification, and characterization of an extracellular endo-P-l,3-glucanase from a monokaryon of Schizophyllutn commune ATCC 38548 defective in exo-P-1,3-glucanase formation. Can. J. Microbiol. 40 : 18-23. Les auteurs ont CtudiC la production d'une activitC P-1,3-glucanase extracellulaire par une souche monocaryote de Schizophyllum cotnmune; les rCsultats ont indiquC que l'activitt P-glucanase est composCe d'une endo-P-l,3-glucanase, en plus d'une quantitC negligeable d'activitC P-1,6-glucanase et P-glucosidase. Contrairement i la production de P-1,3-glucanase de la souche parentale dicaryote de S. commutle ATCC 38548, la synthbse de P-1,3-glucanase du monocaryon n'a pas Ct C dCterminCe par la repression d'un catabolite. L'endo-P-1,3-glucanase du monocaryon a Ct C purifiCe du filtrat de culture par lyophilisation, chromatographie Cchangeuse d'anion sur Mono Q et filtration sur gel de Sephacryl S-100. L'Clectrophorbse en gel dCnaturant de polyacrylamide (SDS-PAGE) a rCvClt une protCine homogbne de masse molCculaire de 3 5 3 kDa et le point isoClectrique a CtC trouvC i 3,95. L'enzyme fut active seulement envers les glucanes contenant des liaisons P-1,3, incluant la lichenane, une p -1 3 1 ...