α-Mannosidase and β-Mannosidase from the Liver of Turbo cortunus: Purification, Properties and Application in Carbohydrate Research

Abstract

The liver of Turbo cortumis contained several glycosidase activities. Sephadex G-200 column chromatography, heating and hydroxylapatite column chromatography were effective for the separation of the glyco-sidases from each other. α-Mannosidase [EC 3.2.1.24] from the liver of T. cortunus was purified 130-fold, using p-nitrophenyl α-D-mannoside as substrate. The purified α-mannosidase was practically free from all other glycosidases tested. The enzyme released 64—66% of the mannose from ovalbumin glycopeptide. It also released mannose from pronase digest of Taka-amylase A [EC 3.2.1.1] and a mannosyl rhamnose, which is a part of the repeating oligosaccharide unit of the O-antigenic lipopolysaccharide in Salmonella typhimurium. The enzyme did not attack yeast mannan. β-Mannosidase [EC 3.2.1.25] from the liver of T. cortunus was purified 63-fold, using phenyl β-D-mannoside as substrate. The purified β-mannosidase was practically free from all other glycosidases tested. The enzyme hydrolyzed none of the four compounds mentioned above.