Formaldehyde Ferredoxin Oxidoreductase
Formaldehyde ferredoxin oxidoreductase (FOR) is a homotetramer where each subunit contains a [4Fe–4S] cluster and a mononuclear tungsten atom coordinated by the dithioline groups of two pterin molecules. It is a member of a family of five closely related tungstoenzymes found in organisms that grow at high temperatures in marine volcanic vents. FOR catalyzes the two-electron oxidation of its aldehyde substrate to the corresponding acid with the concomitant reduction of ferredoxin, its physiological electron acceptor. FOR oxidizes short chain C_1-C_4 aldehydes as substrates but has the highest affinity for C_4-C_6 di- and semialdehydes. The enzyme is proposed to have a role in peptide metabolism.