In some bacteria, a single protein catalyses both this activity and that of EC
6.3.2.17, tetrahydrofolate synthase [2], the combined activity of which leads to the formation of the coenzyme polyglutamated tetrahydropteroate (H4PteGlun), i.e. various tetrahydrofolates. In contrast, the activities are located on separate proteins in most eukaryotes studied to date [3]. This enzyme is reponsible for attaching the first glutamate residue to dihydropteroate to form dihydrofolate and is present only in those organisms that have the ability to synthesize tetrahydrofolate de novo, e.g. plants, most bacteria, fungi and protozoa [3].
