<p>Pteridine reductase is an enzyme used by trypanosomatids (including <taxon tax_id="5693">Trypanosoma cruzi</taxon> and <taxon tax_id="5664">Leishmania major</taxon>) to obtain reduced pteridines by salvage rather than biosynthetic pathways. Enzymes in T. cruzi described as pteridine reductase 1 (PTR1) and pteridine reductase 2 (PTR2) have different activity profiles. PTR1 is more active with fully oxidized biopterin and folate than with reduced forms, while PTR2 reduces dihydrobiopterin and dihydrofolate but not oxidized pteridines. T. cruzi PTR1 and PTR2 are more similar to each other in sequence than either is to the pteridine reductase of L. major, and all are included in this family.</p>