title: Purification and characterization of an exo-beta-1,3-glucanase produced by Trichoderma asperellum.
abstract: Trichoderma asperellum produces at least two extracellular beta-1,3-glucanases upon induction with cell walls from Rhizoctonia solani. A beta-1,3-glucanase was purified by gel filtration and ion exchange chromatography. A typical procedure provided 35.7-fold purification with 9.5% yield. The molecular mass of the purified exo-beta-1,3-glucanases was 83.1 kDa as estimated using a 12% (w/v) SDS-electrophoresis slab gel. The enzyme was only active toward glucans containing beta-1,3-linkages and hydrolyzed laminarin in an exo-like fashion to form glucose. The K(m) and V(max) values for exo-beta-1,3-glucanase, using laminarin as substrate, were 0.087 mg ml(-1) and 0.246 U min(-1), respectively. The pH optimum for the enzyme was pH 5.1 and maximum activity was obtained at 55 degrees C. Hg(2+) strongly inhibited the purified enzyme.
authors.affiliation: Faculdade de Farmácia, Universidade Federal de Goiás, 74.605-220, Goiânia, GO, Brazil. mbara@farmacia.ufg.br
authors.forename: Maria Teresa F
authors.initials: MT
authors.lastname: Bara
authors.forename: Adilson L
authors.initials: AL
authors.lastname: Lima
authors.forename: Cirano J
authors.initials: CJ
authors.lastname: Ulhoa
mesh_terms: D002244:Carbon / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D004790:Enzyme Induction; D015966:Gene Expression Regulation, Fungal; D043326:Glucan 1,3-beta-Glucosidase; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012232:Rhizoctonia / Q000378:metabolism; D012988:Soil Microbiology; D014242:Trichoderma / Q000201:enzymology* / Q000254:growth & development
chemical_list: D002244:Carbon; D006026:Glycoside Hydrolases; D043326:Glucan 1,3-beta-Glucosidase; C117648:beta-1,3-exoglucanase