Effect of substrate concentration on the enantioselectivity of cyclohexanone monooxygenase from Acinetobacter calcoaceticus and its rationalization

Abstract The ee values of lactone 3 , and not of lactone 2 , obtained from the enantiodivergent oxidation of racemic bicyclo[3.2.0]hept-2-en-6-one 1 , catalyzed by cyclohexanone monooxygenase from Acinetobacter calcoaceticus , were found to be markedly dependent on the degree of conversion and substrate concentration. The results are rationalized on the basis of a model which hypothesizes the binding of a second substrate molecule to an enzyme site distinct from the catalytic site.