IUBMB Enzyme Nomenclature


Accepted name: sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming)

Reaction: (1) L-erythro-7,8-dihydrobiopterin + NADP+ = sepiapterin + NADPH + H+
(2) L-erythro-tetrahydrobiopterin + 2 NADP+ = 6-pyruvoyl-5,6,7,8-tetrahydropterin + 2 NADPH + 2 H+

For diagram of reaction click here

Glossary: sepiapterin = 2-amino-6-lactoyl-7,8-dihydropteridin-4(3H)-one
tetrahydrobiopterin = 5,6,7,8-tetrahydrobiopterin = 2-amino-6-(1,2-dihydroxypropyl)-5,6,7,8-tetrahydropteridin-4(3H)-one

Other name(s): SR

Systematic name: L-erythro-7,8-dihydrobiopterin:NADP+ oxidoreductase

Comments: This enzyme catalyses the final step in the de novo synthesis of tetrahydrobiopterin from GTP. The enzyme, which is found in higher animals and some fungi and bacteria, produces the erythro form of tetrahydrobiopterin. cf. EC, sepiapterin reductase (L-threo-7,8-dihydrobiopterin forming).

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9059-48-7


1. Katoh, S. Sepiapterin reductase from horse liver: purification and properties of the enzyme. Arch. Biochem. Biophys. 146 (1971) 202-214. [PMID: 4401291]

2. Matsubara, M., Katoh, S., Akino, M. and Kaufman, S. Sepiapterin reductase. Biochim. Biophys. Acta 122 (1966) 202-212. [PMID: 5969298]

3. Werner, E.R., Schmid, M., Werner-Felmayer, G., Mayer, B. and Wachter, H. Synthesis and characterization of 3H-labelled tetrahydrobiopterin. Biochem. J. 304 (1994) 189-193. [PMID: 7528005]

4. Kim, Y.A., Chung, H.J., Kim, Y.J., Choi, Y.K., Hwang, Y.K., Lee, S.W. and Park, Y.S. Characterization of recombinant Dictyostelium discoideum sepiapterin reductase expressed in E. coli. Mol. Cells 10 (2000) 405-410. [PMID: 10987137]

[EC created 1972, modified 2012]

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