IUBMB Enzyme Nomenclature


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

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

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

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

Comments: This enzyme, isolated from the bacterium Chlorobium tepidum, catalyses the final step in the de novo synthesis of tetrahydrobiopterin from GTP. cf. EC, sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming).

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, CAS registry number:


1. Cho, S.H., Na, J.U., Youn, H., Hwang, C.S., Lee, C.H. and Kang, S.O. Sepiapterin reductase producing L-threo-dihydrobiopterin from Chlorobium tepidum. Biochem. J. 340 (1999) 497-503. [PMID: 10333495]

2. Supangat, S., Choi, Y.K., Park, Y.S., Son, D., Han, C.D. and Lee, K.H. Expression, purification, crystallization and preliminary X-ray analysis of sepiapterin reductase from Chlorobium tepidum. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 61 (2005) 202-204. [PMID: 16510994]

[EC created 2012]

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