Steroid desmolase synthesis by Eubacterium desmolans and Clostridium cadavaris

The synthesis of a steroid desmolase was demonstrated in two obligate anaerobes: a new bacterial species, Eubacterium desmolans, isolated from cat fecal flora, and Clostridium cadavaris, recovered from sewage of New York City. The enzyme cleaves the C-17-C-20 bond of corticoids possessing hydroxyl functions at C-17 and C-21. The conversion is quantitative, provided the substrate concentration is less than 100 micrograms/ml and the organisms are in the log phase. The velocity of transformation parallels the bacterial growth curve and in the log phase is higher for E. desmolans than for C. cadavaris. In addition, both organisms synthesize a 20 beta-hydroxysteroid dehydrogenase.