Fungal glycosidases. V. Purification and properties of an extracellular exo-(1.RAR.3)-.BETA.-D-glucosidase from Trichophyton mentagrophytes.

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Abstract
An exo(1 .fwdarw. 3)-.beta.-D-glucosidase was isolated from the culture filtrate of the fungus T. mentagrophytes [a cutaneous lesion causing fungus] by ammonium sulfate fractionation, gel chromatography on Sephadex G-200 equilibrated with 0.1 M sodium phosphate buffer (pH 7.5), and ion exchange chromatography on DEAE-Sephadex A-50. The enzyme was purified 304 fold, with a recovery of 15%. The Km value of the enzyme with p-nitrophenyl-.beta.-D-glucospyranoside was 3.1 mM. The enzyme was strongly inhibited by Ag+, Hg2+, Cu2+ and Co2+ ions and also by N-bromosuccinimide and I2. This enzyme hydrolyzed p-nitrophenyl-.beta.-D-glucopyranoside but did not show any activity towards p-nitrophenyl-.alpha.-D-glucopyranoside or other p-nitrophenyl-glycosides. The enzymes also hydrolyzed (1 .fwdarw. 3)-.beta.-linked glucosides, but not (1 .fwdarw. 4)-.beta.- and (1 .fwdarw. 6)-.beta.-linked glucosides. When the enzyme hydrolyzed (1 .fwdarw. 3)-.beta.-linked oligo and polyglucosides, the only product identified by paper chromatography was glucose monomer. The MW of the enzyme, as determined by sodium dodecyl sulfate disc gel electrophoresis, was 4.9 .times. 104 daltons.