ABSTRACT
The substrate specificity of the steroid ketone monooxygenase indicates that the reactivity of the monooxygenase with substituted steroids appears to be dependent on the position of the substituted polar groups. This chapter summarizes the purification procedure of the enzyme from the cells of Cylindrocarpon radicicola ATCC 11011, grown in the presence of progesterone, with a dehydroepiandrosterone-linked Sepharose 4B column. Prairie and Talalay obtained an enzyme extract from Penicillium lilacinum capable of catalyzing an NADPH-dependent oxidation of androstenedione to form testololactone. The enzyme catalyzes formation of 1.1 pmol of testosterone acetate from progesterone per minute per milligram of protein under the standard assay conditions. The flavin moiety of the enzyme was identified as flavine adenine dinucleotide by its Rf-value on thin layer chromatography. The fluorescence spectrum of purified enzyme has excitation peaks at 444 nm and 385 nm, and an emission peak at 525 nm.
