In enzymology, coproporphyrinogen dehydrogenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are coproporphyrinogen III and S-adenosyl methionine (SAM). Its products are protoporphyrinogen IX, carbon dioxide, methionine, and 5'-deoxyadenosine. It is an example of a radical SAM enzyme.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with other acceptors. The systematic name of this enzyme class is coproporphyrinogen-III:S-adenosyl-L-methionine oxidoreductase (decarboxylating). Other names in common use include oxygen-independent coproporphyrinogen-III oxidase, HemF, HemN, radical SAM enzyme, and coproporphyrinogen III oxidase. This enzyme participates in the biosynthesis of porphyrins and chlorophyll. HemN is the oxygen-independent oxidase produced in Escherichia coli. HemF is the oxygen-dependent oxidase within E. coli. Importantly, only HemN utilizes S-adenosyl methionine. Human variants of Coproporphyrinogen oxidase are cofactor-independent.