Abstract
The β-D-mannosidase (β-D-mannoside mannohydrolase, [EC 3 .2.1.25]) from culture filtrate of Aspeygillus aculeatus was purified with ammonium sulfate precipitation and column chromatographies with DEAE-Sephadex A-50, Sephacryl S-200, and preparative isoelectric focusing. The enzyme has a molecular weight of 130, 000 (SDS-PAGE) and an isoelectric point of pH 4 .0. The enzyme shows maximum activity at pH 2.0 and at 70°C, and is stable for 30 min at 50°C and between pH 4 to 7.Enzyme activity was completely inhibited by Ag+, Pb2+, and Hg2+ The β-mannosidase has high specificity towards p-nitrophenyl fl-D-mannopyranoside and mannooligosaccharides .
