Purification and Characterization of the Alkene Monooxygenase from Nocardia corallina B-276

Alkene monooxygenase from the propene utilizer Nocardia corallina B-276 was separated into three components, and all components were purified to homogeneity and their properties were examined. The epoxidase, with a molecular mass of 95 kDa, was considered to catalyze the oxidation of the substrate propene to propylene oxide. It consisted of 53- and 35-kDa subunits, which contained approximately 2-mol of non-heme iron per mole of protein. The reductase, molecular mass 40 kDa, was found to contain an FAD and an Fe₂ S₂ cluster. A third protein, which we have called the coupling protein, with a mass of 14 kDa, appears to function as a regulator of activity. The purified AMO system required NADH as an electron donor, and catalyzed alkene epoxidation only. Acetylene, a specific inhibitor for methane monooxygenase, did not inhibit the AMO activity.