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

The ee values of lactone 3, and not of lactone 2, obtained from the enantio divergent oxidation of racemic bicyclo[3.2.0]hept-2-en-6-one 1, catalyzed b y cyclohexanone monooxygenase from Acinetobacter calcoaceticus, were found to be markedly dependent on the degree of conversion and substrate concentr ation. The results are rationalized on the basis of a model which hypothesi zes the binding of a second substrate molecule to an enzyme site distinct f rom the catalytic site. (C) 2000 Elsevier Science Ltd. All rights reserved.