title: Enzymes of carbohydrate metabolism of mycelial fungi from marine environments. beta-1,3-glucanase of the marine fungus Chaetomium indicum.
abstract: Thirty samples of fungi belonging to 17 species living in marine environments were studied for their ability to produce extracellular enzymes. In the culture fluids, a variety of glycosidases (beta-glucosidases, N-acetyl-beta-glucosaminidase, beta-galactosidases, and alpha-mannosidases) and glucanases (amylases and beta-1,3-glucanases) were found. Several cultures were found that could be used as efficient producers of either individual enzymes or a whole complement of enzymes degrading carbohydrate-containing compounds. Optimal growth conditions for the fungus Chaetomium indicum and beta-1,3-glucanase biosynthesis were developed. beta-1,3-Glucanase was isolated by a combination of ion-exchange chromatography, ultrafiltration, and gel chromatography. The molecular mass of the enzyme determined by gel-filtration was 54 kD. The enzyme was stable at temperatures below 50 degrees C, had a temperature optimum for activity at 60 degrees C, and retained activity between pH 4.5 and 7.5. The pH dependence of the beta-1, 3-glucanase activity showed two maxima, at pH 4.4 and 5.6; this suggested the existence of two forms of the enzyme. Analysis of the products of enzymatic hydrolysis of laminaran, transglycosylating ability, and the effect of a specific natural inhibitor indicates that both forms are exo-beta-1,3-glucanases.
authors.affiliation: Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, pr. 100-letiya Vladivostoka 159, Vladivostok, 690022, Russia.
authors.forename: Y V
authors.initials: YV
authors.lastname: Burtseva
authors.forename: V V
authors.initials: VV
authors.lastname: Sova
authors.forename: M V
authors.initials: MV
authors.lastname: Pivkin
authors.forename: T N
authors.initials: TN
authors.lastname: Zvyagintseva
mesh_terms: D050260:Carbohydrate Metabolism; D002597:Chaetomium / Q000201:enzymology*; D004795:Enzyme Stability; D043326:Glucan 1,3-beta-Glucosidase; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D001617:beta-Glucosidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D006026:Glycoside Hydrolases; D001617:beta-Glucosidase; D043326:Glucan 1,3-beta-Glucosidase