Highly regioselective glucosylation of 2'-deoxynucleosides by using the crude β-glycosidase from bovine liver.

An enzymatic regioselective approach for the glucosylation of a series of 2'-deoxynucleosides was described by using the crude β-glycosidase from bovine liver that is less expensive and can be simply prepared in a standard organic laboratory. With the glucosylation of 2'-deoxyuridine as a model reaction, the effects of several key factors on the enzymatic reaction were examined. The optimum enzyme dosage, buffer pH and temperature were 0.05U/ml, 9.5 and 42°C, respectively. The presence of alkali β-glycosidase as the main active component in the crude enzyme extract might account for the high glucosylation activity at pH 9.5. In addition, the desired 5'-O-glucosylated derivatives of 2'-deoxynucleosides were synthesized with the yields of 22-72% and exclusive 5'-regioselectivities (>99%).