Tetrahydrofolic Acid (THFA)

Tetrahydrofolic acid is a folic acid derivative.It is a coenzyme in many reactions, especially in the metabolism of amino acids and nucleic acids. It acts as a donor of a group with one carbon atom. It gets this carbon atom by sequestering formaldehyde produced in other processes. A shortage in THF can cause megaloblastic anemia.

Tetrahydrofolic acid is reduced by the drug methotrexate, which is used to impair nucleotide synthesis. This drug is a potent chemotherapy and anti rheumatic.

Tetrahydrofolic acid is involved in the conversion of formiminoglutamic acid to glutamic acid; this may reduce the amount of histidine available for decarboxylation and protein synthesis, and hence the urinary histamine and formiminoglutamic acid may be decreased.