Sepiapterin reductase

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Protein SPR PDB 1z6z.png
Available structures
PDBOrtholog search: PDBe RCSB
AliasesSPR, SDR38C1, sepiapterin reductase (7,8-dihydrobiopterin:NADP+ oxidoreductase), sepiapterin reductase
External IDsOMIM: 182125 MGI: 103078 HomoloGene: 37735 GeneCards: SPR
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 2: 72.89 – 72.89 MbChr 6: 85.11 – 85.11 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Sepiapterin reductase is an enzyme that in humans is encoded by the SPR gene.[5][6][7]


Sepiapterin reductase (7,8-dihydrobiopterin:NADP+ oxidoreductase; EC catalyzes the NADPH-dependent reduction of various carbonyl substances, including derivatives of pteridines, and belongs to a group of enzymes called aldo-keto reductases. SPR plays an important role in the biosynthesis of tetrahydrobiopterin.[7]


sepiapterin reductase
Sepiapterin reductase homodimer, Human
EC no.
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

Sepiapterin reductase (SPR) catalyzes the chemical reaction

L-erythro-7,8-dihydrobiopterin + NADP+ sepiapterin + NADPH + H+

Thus, the two substrates of this enzyme are L-erythro-7,8-dihydrobiopterin and NADP+, whereas its three products are sepiapterin, NADPH, and a single hydrogen ion (H+).

This enzyme belongs to the family of oxidoreductases, to be specific, those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 7,8-dihydrobiopterin:NADP+ oxidoreductase. This enzyme participates in folate biosynthesis.


Clinical significance[edit]

Mutations of the SPR gene may cause sepiapterin reductase deficiency, a rare disease. The clinical phenotype can include progressive psychomotor retardation, altered tone, seizures, choreoathetosis, temperature instability, hypersalivation, microcephaly, and irritability. Patients with sepiapterin reductase deficiency also manifest dystonia with diurnal variation, oculogyric crises, tremor, hypersomnolence, oculomotor apraxia, and weakness.[9] Response to treatment is variable and the long-term and functional outcome is unknown. To provide a basis for improving the understanding of the epidemiology, genotype/phenotype correlation and outcome of these diseases their impact on the quality of life of patients, and for evaluating diagnostic and therapeutic strategies a patient registry was established by the noncommercial International Working Group on Neurotransmitter Related Disorders (iNTD).[10]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000116096 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000033735 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Ichinose H, Katoh S, Sueoka T, Titani K, Fujita K, Nagatsu T (Oct 1991). "Cloning and sequencing of cDNA encoding human sepiapterin reductase--an enzyme involved in tetrahydrobiopterin biosynthesis". Biochem Biophys Res Commun. 179 (1): 183–189. doi:10.1016/0006-291X(91)91352-D. PMID 1883349.
  6. ^ Persson B, Kallberg Y, Bray JE, Bruford E, Dellaporta SL, Favia AD, Duarte RG, Jornvall H, Kavanagh KL, Kedishvili N, Kisiela M, Maser E, Mindnich R, Orchard S, Penning TM, Thornton JM, Adamski J, Oppermann U (Feb 2009). "The SDR (short-chain dehydrogenase/reductase and related enzymes) nomenclature initiative". Chem Biol Interact. 178 (1–3): 94–98. doi:10.1016/j.cbi.2008.10.040. PMC 2896744. PMID 19027726.
  7. ^ a b "Entrez Gene: SPR sepiapterin reductase (7,8-dihydrobiopterin:NADP+ oxidoreductase)".
  8. ^ "BRENDA - Information on EC - sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming)".
  9. ^ Pearl PL, Taylor JL, Trzcinski S, Sokohl A (May 2007). "The pediatric neurotransmitter disorders". J Child Neurol. 22 (5): 606–616. doi:10.1177/0883073807302619. PMID 17690069. S2CID 10689202.
  10. ^ "Patient registry".

Further reading[edit]

External links[edit]

  • Overview of all the structural information available in the PDB for UniProt: P35270 (Human Sepiapterin reductase) at the PDBe-KB.
  • Overview of all the structural information available in the PDB for UniProt: Q64105 (Mouse Sepiapterin reductase) at the PDBe-KB.