In enzymology, a pteridine reductase (EC 1.5.1.33) is an enzyme that catalyzes the chemical reaction

5,6,7,8-tetrahydrobiopterin + 2 NADP⁺ biopterin + 2 NADPH + 2 H⁺

Thus, the two substrates of this enzyme are 5,6,7,8-tetrahydrobiopterin and NADP⁺, whereas its 3 products are biopterin, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 5,6,7,8-tetrahydrobiopterin:NADP+ oxidoreductase. Other names in common use include PTR1, and pteridine reductase 1.

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1W0C, 2BF7, 2BFA, 2BFM, 2BFO, 2BFP, and 2C7V.

• Nare B, Hardy LW, Beverley SM (1997). "The roles of pteridine reductase 1 and dihydrofolate reductase-thymidylate synthase in pteridine metabolism in the protozoan parasite Leishmania major". J. Biol. Chem. 272 (21): 13883–91. doi:10.1074/jbc.272.21.13883. PMID 9153248.
• Gourley DG, Schüttelkopf AW, Leonard GA, Luba J, Hardy LW, Beverley SM, Hunter WN (2001). "Pteridine reductase mechanism correlates pterin metabolism with drug resistance in trypanosomatid parasites". Nat. Struct. Biol. 8 (6): 521–5. doi:10.1038/88584. PMID 11373620. S2CID 32379320.
• Fitzpatrick PF (2000). "The Aromatic Amino Acid Hydroxylases". Advances in Enzymology and Related Areas of Molecular Biology. Advances in Enzymology - and Related Areas of Molecular Biology. Vol. 74. pp. 235–94. doi:10.1002/9780470123201.ch6. ISBN 978-0-470-12320-1. PMID 10800597. {{cite book}}: |journal= ignored (help)