Proteins containing this domain include dihydropteroate synthase (EC 2.5.1.15) as well as a group of methyltransferase enzymes including methyltetrahydrofolate, corrinoid iron-sulphur protein methyltransferase (MeTr)[1] that catalyses a key step in the Wood-Ljungdahl pathway of carbon dioxide fixation.

Dihydropteroate synthase (EC 2.5.1.15) (DHPS) catalyses the condensation of 6-hydroxymethyl-7,8-dihydropteridine pyrophosphate to para-aminobenzoic acid to form 7,8-dihydropteroate.

DHPS is the target of sulfonamides, which are substrate analogues that compete with para-aminobenzoic acid.

Bacterial DHPS (gene sul or folP)[2] is a protein of about 275 to 315 amino acid residues that is either chromosomally encoded or found on various antibiotic resistance plasmids.

In the fungus Pneumocystis jirovecii (previously P. carinii) DHPS is the C-terminal domain of a multifunctional folate synthesis enzyme (gene fas).