Molybdoenzyme that catalyzes the anaerobic hydroxylation of a tertiary carbon atom in the side chain of cholesterol

Abstract

Background: Cholesterol degradation is challenging due to its complex structure and low water solubility. Results: C25 dehydrogenase is a novel molybdenum/iron-sulfur/heme-containing enzyme that hydroxylates the tertiary C25 of the steroid side chain. Conclusion: C25 dehydrogenase and related enzymes identified in the genome of Sterolibacterium denitrificans replace oxygenases in anaerobic and even aerobic steroid metabolism. Significance: O2-independent hydroxylations by molybdoenzymes probably represent a general strategy to activate steroid substrates anaerobically. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.