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Updated: Sep 22, 2025

Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
Cysteine Dealkylation in Bacillus subtilis by a Novel Flavin-Dependent Monooxygenase
Sohan Hazra1, Dhananjay M Bhandari1, Kalyanaraman Krishnamoorthy1
1Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.
Abstract:
In this paper, we describe the biochemical reconstitution of a cysteine salvage pathway and the biochemical characterization of each of the five enzymes involved. The salvage begins with amine acetylation of S-alkylcysteine, followed by thioether oxidation. The C-S bond of the resulting sulfoxide is cleaved using a new flavoenzyme catalytic motif to give N-acetylcysteine sulfenic acid. This is then reduced to the thiol and deacetylated to complete the salvage pathway. We propose that this pathway is important in the catabolism of alkylated cysteine generated by proteolysis of alkylated glutathione formed in the detoxification of a wide range of electrophiles.
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