Separation and properties of alpha-mannosidase and mannanase from the basidiomycete Phellinus abietis

Abstract

Proteins of a crude enzyme preparation obtained from the cultivation medium of the basidiomycete Phellinus abietis were separated by gel filtration and ion-exchange chromatography. The preparation contained a minimum of three enzymes capable of splitting alpha-D-mannosidic bonds: alpha-mannosidase, exomannanase, and endomannanase, which were separated. Some properties of the mannanase complex of the crude enzyme preparation, and of a partially purified alpha-mannosidase were examined. The mannanase complex exhibited two pH optima, its temperature optimum being at 45 degrees C. The pH optimum of purified alpha-mannosidase was at pH 5.0, the temperature optimum being at 45 degrees C. The pH optimum of purifed alpha-mannosidase was at pH 5.0, the temperature optimum at at 60 degrees C; the enzyme had a relatively high heat stability. The Km of alpha-mannosidase for p-nitrophenyl alpha-D-mannopyranoside was 1.5 X 10(-5) M. Pure alpha-mannosidase did not split mannan.