Characteristics of 16-dehydroprogesterone reductase in cell extracts of the intestinal anaerobe, Eubacterium sp. strain 144.
16-Dehydroprogesterone reductase (16-DHPR) activity was present in cell extracts of Eubacterium sp. strain 144 only when the organism was grown in the presence of steroids containing a delta 16-17 double bond and C-20-ketone. Cells grown with 16-dehydropregnenolone contained 16-DHPR activity but lacked delta 4-5-3-keto steroid reductase activity. Pyruvate or sodium dithionite served as electron donors for 16-DHPR and both reactions required methyl viologen as an electron carrier. Neither NADH nor NADPH, with or without flavin nucleotides, were used by 16-DHPR. Enzyme activity was detected in the cytoplasmic fraction (40%) and membrane fraction (20%) of crude cell extracts, but 40% of the activity was unaccounted for following ultracentrifugation. 16-DHPR activity was unaffected by pH in potassium phosphate buffer over the range 5.0 to 8.5, but was inhibited by Tris-HCl above pH 7.0. 16-DHPR activity was inhibited by sulfhydryl reagents, but inhibitors of electron transport reactions or metal chelators did not affect the enzyme.
Watkins
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WE
Department of Microbiology, North Dakota State University, Fargo 58105.
Glass
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D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D004227:Dithionite / Q000378:metabolism; D004579:Electron Transport; D005051:Eubacterium / Q000187:drug effects / Q000201:enzymology*; D010088:Oxidoreductases / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D013379:Substrate Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D014461:Ultracentrifugation
D011773:Pyruvates; D013439:Sulfhydryl Reagents; D004227:Dithionite; D019289:Pyruvic Acid; D010088:Oxidoreductases; C067885:16-dehydroprogesterone reductase