The zygomycete fungus Rhizomucor pusillus HHT-1, cultured on L(+)arabinose as a sole carbon source, produced extracellular α-L-arabinofuranosidase. The enzyme was purified by (NH4)2SO4fractionation, gel filtration, and ion exchange chromatography. The molecular mass of this monomeric enzyme was 88 kDa. The native enzyme had a pI of 4.2 and displayed a pH optimum and stability of 4.0 and 7.010.0, respectively. The temperature optimum was 65°C, and it was stable up to 70°C. The Kmand Vmaxfor p-nitrophenyl α-L-arabinofuranoside were 0.59 mM and 387 µmol·min1·mg1protein, respectively. Activity was not stimulated by metal cofactors. The N-terminal amino acid sequence did not show any similarity to other arabinofuranosidases. Higher hydrolytic activity was recorded with p-nitrophenyl α-L-arabinofuranoside, arabinotriose, and sugar beet arabinan; lower hydrolytic activity was recorded with oatspelt xylan and arabinogalactan, indicating specificity for the low molecular mass L(+)-arabinose containing oligosaccharides with furanoside configuration.Key words: α-L-arabinofuranosidase, enzyme purification, amino acid sequence, Rhizomucor pusillus.
Rhizomucor pusillus
