α-Galactosidase from Mortierella vinacea: CRYSTALLIZATION AND PROPERTIES

Abstract

Abstract A simple method has been devised for the isolation of α-galactosidase in crystalline form from the mycelia of Mortierella vinacea. The crystalline α-galactosidase is free from protease and other glycosidases. It gives a single protein band when examined by polyacrylamide gel electrophoresis. The crystalline preparation contains 10.8% neutral sugars and 2.7% d-glucosamine, indicating that the enzyme is glycoprotein in nature. The enzyme is stable at neutral and alkaline pH; however, it becomes unstable below pH 6.0. It hydrolyzes O- and P-nitrophenyl-α-d-galactopyranoside, methyl - α - d - galactopyranoside, galactinol, melibiose, raffinose, stachyose, 4-O-α-d-galactopyranosyl-d-galactose, 6-O-α-d-galactopyranosyl-O-β-d-galactopyranosyl-1-glycerol as well as methyl-β-l-arabinoside, though at a much slower rate. It does not liberate d-galactose from the galactomannan of guar gum, glycopeptide obtained from blood group B substance, or earthworm cuticle collagen. The effects of pH, substrate concentration, inhibitors, and temperature on the catalytic activity of the crystalline enzyme are described.