6,7-dihydropteridine reductase

6,7-dihydropteridine reductase
Identifiers
EC number	1.5.1.34
CAS number	9074-11-7
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / EGO
Search PMC articles PubMed articles NCBI proteins

In enzymology, a 6,7-dihydropteridine reductase (EC 1.5.1.34) is an enzyme that catalyzes the chemical reaction

a 5,6,7,8-tetrahydropteridine + NAD(P)+ $\rightleftharpoons$ a 6,7-dihydropteridine + NAD(P)H + H⁺

The 3 substrates of this enzyme are 5,6,7,8-tetrahydropteridine, NAD⁺, and NADP⁺, whereas its 4 products are 6,7-dihydropteridine, NADH, 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-tetrahydropteridine:NAD(P)+ oxidoreductase. Other names in common use include 6,7-dihydropteridine:NAD(P)H oxidoreductase, DHPR, NAD(P)H:6,7-dihydropteridine oxidoreductase, NADH-dihydropteridine reductase, NADPH-dihydropteridine reductase, NADPH-specific dihydropteridine reductase, dihydropteridine (reduced nicotinamide adenine dinucleotide), reductase, dihydropteridine reductase, dihydropteridine reductase (NADH), and 5,6,7,8-tetrahydropteridine:NAD(P)H+ oxidoreductase. This enzyme participates in folate biosynthesis.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 1YKI, 1YLR, and 1YLU.

Clinical significance

Dihydropteridine reductase deficiency is a defect in the regeneration of tetrahydrobiopterin. Many patients have significant developmental delays despite therapy, develop brain abnormalities, and are prone to sudden death. The reason is not completely clear, but might be related to the accumulation of dihydrobiopterin and abnormal metabolism of folic acid. ^[1] 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). ^[2]

References

1. Longo N (June 2009). "Disorders of biopterin metabolism". J Inherit Metab Dis 32 (2): 333–342. doi:10.1007/s10545-009-1067-2. PMID 19234759.
2. "Patient registry".

• Harano T (1972). "New diaphorases from Bombyx silkworm eggs. NADH/NADPH cytochrome c reductase activity mediated with 6,7-dimethyltetrahydropterin". Insect Biochem. 2 (8): 385–399. doi:10.1016/0020-1790(72)90019-4.
• Hasegawa H. "Dihydropteridine reductase from bovine liver. Purification, crystallization, and isolation of a binary complex with NADH". J. (Tokyo). Biochem. (1): 169–77. PMID 191436.
• Kaufman S; Bridgers, WF; Eisenberg, F; Friedman, S (1962). "Phenylalanine hydroxylase". Methods Enzymol. 5: 809–816. doi:10.1016/s0076-6879(62)05317-3. PMID 14031389.
• Lind KE (1972). "Dihydropteridine reductase. Investigation of the specificity for quinoid dihydropteridine and the inhibition by 2,4-diaminopteridines". Eur. J. Biochem. 25 (3): 560–2. doi:10.1111/j.1432-1033.1972.tb01728.x. PMID 4402916.
• Nakanishi N, Hasegawa H, Watabe S. "A new enzyme, NADPH-dihydropteridine reductase in bovine liver". J. (Tokyo). Biochem. (3): 681–5. PMID 16875.