Formimidoyltetrahydrofolate cyclodeaminase
In enzymology, a formimidoyltetrahydrofolate cyclodeaminase is an enzyme that catalyzes the chemical reaction
Hence, this enzyme has one substrate, 5-formimidoyltetrahydrofolate, and two products, 5,10-methenyltetrahydrofolate and NH3.
This enzyme belongs to the family of lyases, specifically ammonia lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is 5-formimidoyltetrahydrofolate ammonia-lyase . Other names in common use include formiminotetrahydrofolate cyclodeaminase, and 5-formimidoyltetrahydrofolate ammonia-lyase . This enzyme participates in folate metabolism by catabolising histidine and adding to the C1-tetrahydrofolate pool.
In mammals, this enzyme can be found as part of a bifunctional enzyme in a single polypeptide with glutamate formimidoyltransferase, the enzyme activity that catalyses the previous step in the histidine catabolic pathway. This arrangement allows the 5-formimidoyltetrahydrofolate intermediate to move directly from one active site to another without being released into solution, in a process called substrate channeling.As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes,, and.
