Comparative study of the properties of wild type and recombinant cyclohexanone monooxygenase, an enzyme of synthetic interest

Cyclohexanone monooxygenase (CHMO), a flavoenzyme of synthetic interest (it catalyses the NADPH-dependent enantioselective oxidation of ketones and of several heteroatoms such as nitrogen, sulfur, phosphorous and selenium present in organic compounds) previously overexpressed in E. coli (TOP10 pQR239), was purified to homogeneity, as demonstrated by SDS-PAGE and MALDI/TOF analysis, and characterised. The recombinant and the wild type (Acinetobacter) enzymes had identical molecular mass, Km values, pH-activity profile and circular dichroism spectra, but slightly differed for pH- and thermo-stability. The latter findings might be due to a different pattern of proteases contaminating the monooxygenases isolated from the two microorganims.