Scheme 1.
The chemical reactions catalyzed by CDO. (A) CDO catalyzes an iron dependent oxygenation reaction that activates O2 and inserts the two oxygen atoms into the sulfur group of L-cysteine to produce cysteinesulfinate. (B) An uncoupled autocatalytic oxidation leads to the formation of a Cys-Tyr cofactor. This uncoupled reaction is triggered by the presence of L-cysteine and O2.