The Characterization of the Enzymatic Conversion of Steffimycin B to 10-Dihydrosteffimycin B
Slavicek, James M.
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Chaetomium sp: UC®-4634 catalyzes ketonic carbonyl reduction of steffimycin B to 10-dihydrosteffimycin B (Scheme 1). Using cell-free preparation of Chaetomium sp. UC®-4634, the process of ketonic carbonyl reduction has been shown to be TPNH linked and dependent upon the age of the Chaetomium culture used. The cell-free extract from Chaetomium had the highest enzymatic activity when harvested after 48 hours of growth. The reaction rate increased linearly with added crude enzyme protein up to 1.6 mg/ml and was highest at approximately pH 6.0. The . . conversion of steffimycin B to 10-dihydrosteffimycinB was found to be inhibited by potassium phosphate. Chaetomium s.p. UC-4634 was also found to catalyze the ketonic carbonyl reduction of steffimycin to 10-dihydrosteffimycin. The products were isolated by extraction from the reaction mixtures and identified by comparison of their Rf values with those of authentic materials.