Transfer Reaction Catalyzed by Exo-β-1,4-galactanase from Bacillus subtilis(Biological Chemistry)

概要

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A transfer reaction catalyzed by an exo-β-1,4-galactanase from Bacillus subtilis was studied. The enzyme had a broad acceptor specificity and transferred galactobiosyl residues to acceptors such as various alcohols, including hydroxy benzenes and saccharides. Transfer products of glycerol formed by the enzyme were compared with those formed by Escherichia coli β-galactosidase and by Penicillium citrinum endo-galactanase. E. coli enzyme transferred 90% of galactose residues to the primary hydroxyl groups of glycerol and P. citrinum endo-enzyme transferred 80% of saccharide residues to the secondary hydroxyl group. The B. subtilis exo-galactanase was less specific than the other two enzymes and formed two products (1-DG and 2-DG) with a 2-DG/1-DG ratio of about 2. The structures of the saccharides were examined by ^<13>C-nuclear magnetic resonance analysis and by enzymatic hydrolysis. 1-DG and 2-DG were elucidated to be O-β-D-galactosyl-(1→4)-O-β-D-galactosyl-(1→1)-glycerol and O-β-D-galactosyl-(1→4)-O-β-D-galactosyl-(1→2)-glyserol, respectively. The efficiency of the transfer reaction was measured at various concentrations of glycerol using galactotriose as a donor. About 40-75% of galactobiosyl residues were transferred at an acceptor concentration range of 20-100 mg/ml.
社団法人日本農芸化学会の論文
1991-08-23