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Q54GP3

UniProt ID :

Q54GP3

NCBI Taxonomy :

44689

Protein names :

Sepiapterin reductase

Organism :

Dictyostelium discoideum

Taxonomy :

Eukaryota

Subcellular locations :

Cytoplasm;

Length :

267

Gene Ontology :

GO ID	Ontology	Definition	Evidence
GO:0005737	Cellular Component	cytoplasm	IEA
GO:0004757	Molecullar Function	sepiapterin reductase activity	ISS
GO:0006979	Biological Process	response to oxidative stress	IDA
GO:0006729	Biological Process	tetrahydrobiopterin biosynthetic process	IDA

Catalytic activity :

L-erythro-7,8-dihydrobiopterin + NADP⁺ = sepiapterin + NADPH.L-erythro-tetrahydrobiopterin + 2 NADP⁺ = 6-pyruvoyl-5,6,7,8-tetrahydropterin + 2 NADPH.Dictyopterin was not identified in one of the enzymatic assays [PubMed:10987137].

Sequences :

MSKVLAIVTGASKGFGKAIAQEIVKCNPNKNQLIDLVLFARSLDGLKSTKESIETISTNAKVIDLQSLDMSNIPDVELKFKSVLENIKWEEYSKICFFNNHGTLYHLGRIEDFSDFKNIQKDNDTNTTSFVVTTSLLVKKLKELGSQYSSEVTIVNSSSLCAIKAFPTWSLYCSSRAYRDMFFQALSLEYKLNDKFKVLNYSLGVLDTDMQSQVREECSEDDKSFYVGLKNDGKLINPNRSASICSNLVYSHKFETGSHLDYYDLDK

Function :

Catalyzes the production of D-threo-tetrahydrobiopterin (DH4), also known as dictyopterin, and in a much smaller amount that of it's stereoisomer L-erythro-tetrahydrobiopterin (BH4). Prefers 1-oxo-2-D-hydroxypropyl-tetrahydropterin to 6-pyruvoyltetrahydropterin as a substrate, thereby maintaining dominant production of DH4 over BH4 in sufficient supply of an aldose reductase-like enzyme. DH4 represents more than 95% of the total tetrahydrobiopterin production. It has a direct antioxidant function to protect mitochondria against oxidative stress.