Multiple Forms of Cyclohexanone Oxygenase from Nocardia globerula CL1

Abstract

The cyclohexanone 1,2-monooxygenase of Nocardia globerula CL1 exists as two electrophoretically distinct forms. These are present in crude cell extracts and are not artifacts of enzyme purification or electrophoresis. They have been separated in mg amounts by preparative polyacrylamide gel electrophoresis and shown to have essentially identical kinetic, spectral and physical characteristics. They do differ in pH-activity profile and temperature stability. Whether or not they are conformational isoenzymes or arise by gene duplication and divergent evolution has not been established. Cyclohexanone oxygenase constitutes 8% of the soluble protein of induced cells. This high level would correlate well with the presence of duplicate genes. It is proposed that the presence of a large amount of cyclohexanone oxygenase may confer an ecological advantage on the organism.