Biology:Sepiapterin reductase

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Short description: Mammalian protein found in Homo sapiens

A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example

Sepiapterin reductase is an enzyme that in humans is encoded by the SPR gene.[1][2][3]

Function

Sepiapterin reductase (7,8-dihydrobiopterin:NADP+ oxidoreductase; EC 1.1.1.153) 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.[3]

Reaction

sepiapterin reductase
Sepiapterin reductase homodimer, Human
Identifiers
EC number1.1.1.153
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

Sepiapterin reductase (SPR) catalyzes the chemical reaction

Template:Chemrxn

The two substrates of this enzyme are L-erythro-7,8-dihydrobiopterin and oxidised Nicotinamide adenine dinucleotide phosphate (NADP+). Its products are sepiapterin, reduced NADPH, and a proton.[4]

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.[5]

Clinical significance

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.[6] 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).[7]

References

Further reading

  • 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.