Folic acid
Was first isolated in 1941 from several tonnes of spinach leaves (lat. folium = leaf).
Chemically consists of pteridine, p-aminobenzoic acid and glutamate. Further glutamate residues can be attached via the γ-carboxylate group, in which case they are referred to as polyglutamates.
Folic acid also occurs in a reduced form as tetrahydrofolic acid, the actual active form. In its function as a coenzyme, it transfers hydroxymethyl and formyl groups.