Synthesis of <i>O</i>-β-Galactopyranosyl-L-Serine Derivatives Using β-Galactosidase in Aqueous-Organic Reaction Systems
作者:K.-C. Becker、P. Kuhl
DOI:10.1080/07328309908543986
日期:1999.1.1
The galactosylation of amino protected serine methyl ester derivatives by beta-galactosidases from E. coli and A. oryzae in aqueous-organic solvents was investigated. A comparison of enzyme activity in aqueous buffer and in several aqueous-organic mixtures revealed that the presence of an organic solvent normally causes a loss in enzyme activity. When the enzyme is used in suspensions with mainly undissolved lactose, the detrimental influence of an organic solvent is less marked if it does not exceed 25 % of the added mixture with water. Employing organic cosolvents, such as acetonitrile, 2-butanone, acetone or ethyl acetate, we obtained yields of the desired galactosylation products higher than those with the enzyme in purely aqueous solution. The amino protecting group shows a significant influence on the transglycosylation reaction in terms of yield, the best up to 28 % being achieved in the synthesis of Aloc-(Gal beta 1-)Ser-OMe with beta-galactosidase from E. coli in a reaction mixture containing 8 to 15 % organic solvent.