数据之源，洞见之始

Metabolite Card

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Note

Tetrahydrobiopterin (CAS: 17528-72-2), also known as BH4, is an essential cofactor in the synthesis of neurotransmitters and nitric oxide (PMID: 16946131). In fact, it is used by all three human nitric-oxide synthases (NOS) eNOS, nNOS, and iNOS as well as the enzyme glyceryl-ether monooxygenase. It is also essential in the conversion of phenylalanine into tyrosine by the enzyme phenylalanine-4-hydroxylase; the conversion of tyrosine into L-dopa by the enzyme tyrosine hydroxylase; and the conversion of tryptophan into 5-hydroxytryptophan via tryptophan hydroxylase. Specifically, tetrahydrobiopterin is a cofactor for tryptophan 5-hydroxylase 1, tyrosine 3-monooxygenase, and phenylalanine hydroxylase, all of which are essential for the formation of the neurotransmitters dopamine, noradrenaline, and adrenaline. Tetrahydrobiopterin has been proposed to be involved in the promotion of neurotransmitter release in the brain and the regulation of human melanogenesis. A defect in BH4 production and/or a defect in the enzyme dihydropteridine reductase (DHPR) causes phenylketonuria type IV, as well as dopa-responsive dystonias. BH4 is also implicated in Parkinson's disease, Alzheimer's disease, and depression. Tetrahydrobiopterin is present in probably every cell or tissue of higher animals. On the other hand, most bacteria, fungi and plants do not synthesize tetrahydrobiopterin (Wikipedia).