H4B is found in 385 entries

H4B as free ligands, exist in 385 entries. Examples include 1D1V, 1D1W, 1D1X

Find related ligands: Stereoisomers Similar ligands Chemical Structure Search

View summary at Ligand Expo

Chemical Component Summary

Identifiers (6R)-2-amino-6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydropteridin-4(3H)-one
Formula C9 H15 N5 O3
Molecular Weight 241.25 g/mol
Type non-polymer
Isomeric SMILES C[C@H](O)[C@H](O)[C@H]1CNc2nc(N)[nH]c(=O)c2N1
InChI InChI=1S/C9H15N5O3/c1-3(15)6(16)4-2-11-7-5(12-4)8(17)14-9(10)13-7/h3-4,6,12,15-16H,2H2,1H3,(H4,10,11,13,14,17)/t3-,4+,6-/m0/s1

Chemical Details

Formal Charge 0
Atom Count 32
Chiral Atom Count 3
Chiral Atoms C6 C9 C10
Bond Count 33
Aromatic Bond Count 6

Drug Info: DrugBank

DrugBank ID DB00360   (Different stereochemistry)
Name Tetrahydrobiopterin
  • approved
  • investigational
Description Tetrahydrobiopterin or BH4 is a cofactor in the synthesis of nitric oxide. It is also essential in the conversion of phenylalanine to tyrosine by the enzyme phenylalanine-4-hydroxylase; the conversion of tyrosine to L-dopa by the enzyme tyrosine hydroxylase; and conversion of tryptophan to 5-hydroxytryptophan via tryptophan hydroxylase. [Wikipedia]
  • (6R)-2-Amino-6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydropteridin-4(1H)-one
  • 2-Amino-6-(1,2-dihydroxypropyl)-5,6,7,8-tetrahydoro-4(1H)-pteridinone
  • 5,6,7,8 Tetrahydrobiopterin
  • 5,6,7,8-Tetrahydrobiopterin
  • BH4
  • Sapropterin
Salts Tetrahydrobiopterin dihydrochloride
Brand Names
  • Kuvan
  • BH4
  • Biopten
Affected Organism Humans and other mammals
Indication For the treatment of tetrahydrobiopterin (BH4) deficiency.
Pharmacology Tetrahydrobiopterin (BH4) is used to convert several amino acids, including phenylalanine, to other essential molecules in the body including neurotransmitters. Tetrahydrobiopterin deficiency can be caused by mutations in GTP cyclohydrolase 1 (GCH1), 6-pyruvoyl-tetrahydropterin synthase/dimerization cofactor of hepatocyte nuclear factor 1 alpha (PCBD1), 6-pyruvoyltetrahydropterin synthase (PTS), and quinoid dihydropteridine reductase (QDPR) genes. These genes make the enzymes that are critical for producing and recycling tetrahydrobiopterin. If one of the enzymes fails to function correctly because of a gene mutation, little or no tetrahydrobiopterin is produced. As a result, phenylalanine from the diet builds up in the bloodstream and other tissues and can damage nerve cells in the brain. High levels of phenylalanine can result in signs and symptoms ranging from temporary low muscle tone to mental retardation, movement disorders, difficulty swallowing, seizures, behavioral problems, progressive problems with development, and an inability to control body temperature.
Mechanism of action Tetrahydrobiopterin (BH4) is a natural co-factor or co-enzyme for phenylalanine-4-hydroxylase (PAH),Tetrahydrobiopterine, and tryptophan-5-hydroxylase. Tetrahydrobiopterin is also a natural co-factor for nitrate oxide synthase. Therefore BH4 is required for the conversion of phenylalanine to tyrosine, for the production of epinephrine (adrenaline) and the synthesis of the monoamine neuro-transmitters, serotonin, dopamine, and norepinephrine (noradrenaline). It is also involved in apoptosis and other cellular events mediated by nitric oxide production. As a coenzyme, BH4 reacts with molecular oxygen to form an active oxygen intermediate that can hydroxylate substrates. In the hydroxylation process, the co-enzyme loses two electrons and is regenerated in vivo in an NADH-dependent reaction. As a co-factor for PAH, tetrahydrobiopterin allows the conversion of phenylalanine to tyrosine and reduces the level of phenylalanine in the bloodstream, thereby reducing the toxic effects of of this amino acid. Normal serum concentrations of phenylalanine are 100 micomolar, while elevated (toxic) levels are typically >1200 micromolar. Individuals with a deficiency in tetrahydrobiopterin are not able to efficiently convert phenylalanine to tyrosine. The excess levels provided by tetrahydrobiopterin supplementation help improve enzyme efficiency. As a co-factor for tyrosine hydroxylase, BH4 facilitates the conversion of tyrosine to L-dopa while as a co-factor for tryptophan hydroxylase, BH4 allows the conversion of tryptophan to 5-hydroxytryptophan, which is then converted to serotonin.
Route of administration oral
  • Dietary Supplements
  • Supplements
ATC-Code A16AX07
CAS number 17528-72-2
Drug Info/Drug Targets: DrugBank 3.0: a comprehensive resource for 'omics' research on drugs. Knox C, Law V, Jewison T, Liu P, Ly S, Frolkis A, Pon A, Banco K, Mak C, Neveu V, Djoumbou Y, Eisner R, Guo AC, Wishart DS. Nucleic Acids Res. 2011 Jan; 39 (Database issue):D1035-41. | PMID: 21059682