Assessing substrate acceptance and enantioselectivity of yeast reductases in reactions with substituted α-keto β-lactams

A number of yeast (Saccharomyces cerevisiae) strains and yeast reductases overexpressed in Escherichia coli were investigated as bioreductants for several α-keto-β-lactams substituted with aryl and alkyl groups in the 4-position. Two of the yeast reductases were found to accept a majority of the substrates tested, while others were more limited. Although none of the reductases investigated showed both diastero- and enantio-selectivity under the screening conditions, these bioreagents are still useful in reductions of α-keto β-lactams.