title: Induction and characterization of an unusual alpha-D-galactosidase from Talaromyces flavus.
abstract: An extracellular alpha-d-galactosidase from Talaromyces flavus CCF 2686 with extremely broad and unusual acceptor specificity is produced exclusively in the presence of the specific inducer--6-deoxy-D-glucose (quinovose). The procedure for the preparation of this very expensive substance has been modified and optimized. Surprisingly, any of other common alpha-D-galactosidase inducers or substrates, e.g., D-galactose, melibiose and raffinose, did not stimulate its production. The crude alpha-D-galactosidase preparation was purified by anion-exchange chromatography and three isoenzymes with different substrate specificities were identified. The main isoenzyme (alphaGal1) was further purified by cation-exchange chromatography and fully characterized. When compared with other alpha-galactosidases and also with other isoenzymes produced by T. flavus, it showed a markedly different regioselectivity and also negligible hydrolytic activity towards melibiose. Moreover, it was active on polymeric substrates (locust bean gum, guar gum) and significantly inhibited by alpha-D-galactopyranosyl azide, D-galactose, D-xylose, melibiose, methyl alpha- and beta-D-galactopyranoside and lactose.
authors.affiliation: Institute of Microbiology, Academy of Sciences of Czech Republic, Vídenská 1083, CZ-142 20 Prague 4, Czech Republic.
authors.forename: Pavla
authors.initials: P
authors.lastname: Simerská
authors.forename: Daniela
authors.initials: D
authors.lastname: Monti
authors.forename: Ivana
authors.initials: I
authors.lastname: Cechová
authors.forename: Helena
authors.initials: H
authors.lastname: Pelantová
authors.forename: Martina
authors.initials: M
authors.lastname: Macková
authors.forename: Karel
authors.initials: K
authors.lastname: Bezouska
authors.forename: Sergio
authors.initials: S
authors.lastname: Riva
authors.forename: Vladimír
authors.initials: V
authors.lastname: Kren
mesh_terms: D003847:Deoxyglucose / Q000031:analogs & derivatives* / Q000378:metabolism; D004790:Enzyme Induction; D007700:Kinetics; D013379:Substrate Specificity; D032901:Talaromyces / Q000201:enzymology*; D000519:alpha-Galactosidase / Q000096:biosynthesis / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D003847:Deoxyglucose; D000519:alpha-Galactosidase; C037904:6-deoxyglucose