Target type: molecularfunction
Binding to a tetrahydrobiopterin, 5,6,7,8-tetrahydrobiopterin or a derivative thereof; tetrahydrobiopterins are enzyme cofactors that carry electrons in redox reactions. [GOC:BHF, GOC:mah, GOC:rl]
Tetrahydrobiopterin (BH4) binding is a crucial molecular function involved in a variety of enzymatic reactions, primarily those catalyzed by pterin-dependent monooxygenases. These enzymes utilize BH4 as a cofactor, playing a critical role in the hydroxylation of various substrates. The binding of BH4 to the enzyme initiates a complex series of events:
1. **Activation of oxygen:** BH4 facilitates the activation of molecular oxygen (O2) by reducing it to a reactive oxygen species. This activation process involves the transfer of electrons from BH4 to O2, generating a highly reactive oxygen species that can participate in the hydroxylation reaction.
2. **Substrate binding and orientation:** The binding of BH4 to the enzyme creates a specific binding pocket that favors the binding and correct orientation of the substrate molecule. This precise orientation ensures that the substrate is positioned optimally for the hydroxylation reaction.
3. **Hydroxylation catalysis:** The activated oxygen species generated by BH4 then reacts with the substrate, introducing a hydroxyl group (OH) into the substrate molecule. This hydroxylation reaction is the primary function of pterin-dependent monooxygenases and is essential for the biosynthesis of various essential molecules.
4. **BH4 regeneration:** After the hydroxylation reaction, BH4 is oxidized to dihydrobiopterin (BH2). To continue the catalytic cycle, BH2 must be reduced back to BH4. This regeneration process is typically catalyzed by dihydrofolate reductase (DHFR), an enzyme that utilizes NADPH as a reducing agent.
The binding of BH4 to these enzymes is highly specific and involves a complex interplay of hydrogen bonding, hydrophobic interactions, and electrostatic forces. This intricate binding process ensures the efficient and precise delivery of oxygen to the substrate, enabling the highly specific hydroxylation reactions catalyzed by pterin-dependent monooxygenases. These enzymes play critical roles in various metabolic pathways, including the biosynthesis of neurotransmitters like dopamine, serotonin, and norepinephrine, as well as the metabolism of aromatic amino acids and steroids. Therefore, understanding the molecular function of tetrahydrobiopterin binding is essential for comprehending the intricate workings of these crucial enzymatic reactions.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Nitric oxide synthase, inducible | A nitric oxide synthase, inducible that is encoded in the genome of human. [PRO:WCB, UniProtKB:P35228] | Homo sapiens (human) |
| Nitric oxide synthase, brain | A nitric oxide synthase 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P29475] | Homo sapiens (human) |
| Nitric oxide synthase, endothelial | A nitric oxide synthase 3 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P29474] | Homo sapiens (human) |
| Tyrosine 3-monooxygenase | A tyrosine 3-monooxygenase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P07101] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| imidazole | 1H-imidazole : An imidazole tautomer which has the migrating hydrogen at position 1. imidazole: RN given refers to parent cpd | imidazole | |
| s,s'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea | S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea: structure in first source | ||
| n-(3-(aminomethyl)benzyl)acetamidine | N-(3-(aminomethyl)benzyl)acetamidine: structure in first source N-[3-(aminomethyl)benzyl]acetamidine : An aralkylamine that is Nbenzylacetamidine substituted at position 3 on the benzene ring by an aminomethyl group. An inhibitor of nitric oxide synthase. | aralkylamine; carboxamidine; primary amino compound | angiogenesis inhibitor; EC 1.14.13.39 (nitric oxide synthase) inhibitor; geroprotector |
| 2-amino-4-picoline | 2-amino-4-picoline: RN given refers to parent cpd | ||
| 3-bromo-7-nitroindazole | |||
| 7-nitroindazole | 7-nitroindazole: an inhibitor of nitric oxide synthase; exhibits anti-nociceptive activity without increasing blood pressure | ||
| beta-aminoethyl isothiourea | beta-Aminoethyl Isothiourea: A radiation-protective agent that can inhibit DNA damage by binding to the DNA. It also increases the susceptibility of blood cells to complement-mediated lysis. | ||
| pimagedine | aminoguanidine : A one-carbon compound whose unique structure renders it capable of acting as a derivative of hydrazine, guanidine or formamide. pimagedine: diamine oxidase & nitric oxide synthase inhibitor; an advanced glycosylation end product inhibitor; used in the treatment of diabetic complications; structure | guanidines; one-carbon compound | EC 1.14.13.39 (nitric oxide synthase) inhibitor; EC 1.4.3.4 (monoamine oxidase) inhibitor |
| 2-aminothiazole | 1,3-thiazol-2-amine : A primary amino compound that is 1,3-thiazole substituted by an amino group at position 2. 2-aminothiazole: RN given refers to parent cpd; structure | 1,3-thiazoles; primary amino compound | |
| s-ethyl n-(4-(trifluoromethyl)phenyl)isothiourea | S-ethyl N-(4-(trifluoromethyl)phenyl)isothiourea: structure in first source | ||
| guanethidine | guanethidine : A member of the class of guanidines in which one of the hydrogens of the amino group has been replaced by a 2-azocan-1-ylethyl group. guanethidine sulfate : A organic sulfate salt composed of two molecules of guanethidine and one of sulfuric acid. Guanethidine: An antihypertensive agent that acts by inhibiting selectively transmission in post-ganglionic adrenergic nerves. It is believed to act mainly by preventing the release of norepinephrine at nerve endings and causes depletion of norepinephrine in peripheral sympathetic nerve terminals as well as in tissues. | azocanes; guanidines | adrenergic antagonist; antihypertensive agent; sympatholytic agent |
| etiron | etiron: a nitric oxide synthase inhibitor; RN given refers to parent cpd; structure | ||
| s-methylisothiopseudouronium | S-methylisothiopseudouronium: inhibits nitric oxide synthase; structure in first source | ||
| arginine | arginine : An alpha-amino acid that is glycine in which the alpha-is substituted by a 3-guanidinopropyl group. Arginine: An essential amino acid that is physiologically active in the L-form. | arginine; glutamine family amino acid; L-alpha-amino acid; proteinogenic amino acid | biomarker; Escherichia coli metabolite; micronutrient; mouse metabolite; nutraceutical |
| indazoles | Indazoles: A group of heterocyclic aromatic organic compounds consisting of the fusion of BENZENE and PYRAZOLES. | indazole | |
| citrulline | citrulline : The parent compound of the citrulline class consisting of ornithine having a carbamoyl group at the N(5)-position. | amino acid zwitterion; citrulline | Daphnia magna metabolite; EC 1.14.13.39 (nitric oxide synthase) inhibitor; Escherichia coli metabolite; human metabolite; micronutrient; mouse metabolite; nutraceutical; plant metabolite; protective agent; Saccharomyces cerevisiae metabolite |
| alpha-aminopyridine | alpha-aminopyridine: RN given refers to parent cpd; structure in Merck Index, 9th ed, #485 aminopyridine : Compounds containing a pyridine skeleton substituted by one or more amine groups. | ||
| oleanolic acid | hydroxy monocarboxylic acid; pentacyclic triterpenoid | plant metabolite | |
| 1,2-Dihydroquinolin-2-imine | aminoquinoline | ||
| 2-amino-3-methylpyridine | 2-amino-3-methylpyridine: structure in first source | ||
| 2-aminothiazoline | 2-aminothiazoline: RN given refers to parent cpd; structure in first source & in Negwer, 5th ed, #97 4,5-dihydro-1,3-thiazol-2-amine : A 1,3-thiazole that is 4,5-dihydro-1,3-thiazole substituted by an amino group at position 2. | 1,3-thiazoles; primary amino compound | |
| guanoxan | guanoxan: was MH 1976-92 (see under GUANIDINES 1976-90); use GUANIDINES to search GUANOXAN 1976-92; antihypertensive agent similar in its mechanism of action to guanethidine; may cause liver damage | benzodioxine | |
| 5-nitroindazole | |||
| 6-nitroindazole | |||
| guanadrel | guanadrel : A spiroketal resulting from the formal condensation of the keto group of cyclohexanone with the hydroxy groups of 1-(2,3-dihydroxypropyl)guanidine. A postganglionic adrenergic blocking agent formerly used (generally as the sulfate salt) for the management of hypertension, it has been largely superseded by other drugs less likely to cause orthostatic hypotension (dizzy spells on standing up or stretching). guanadrel: RN given refers to parent cpd; structure | guanidines; spiroketal | adrenergic antagonist; antihypertensive agent |
| ng-nitroarginine methyl ester | NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension. | alpha-amino acid ester; L-arginine derivative; methyl ester; N-nitro compound | EC 1.14.13.39 (nitric oxide synthase) inhibitor |
| n-(4-nitrophenacyl)imidazole | N-(4-nitrophenacyl)imidazole: structure in first source | ||
| 1-aminoisoquinoline | |||
| 6-aminoindazole | 6-aminoindazole: depresses gastric acid secretion; structure given in first source | indazoles | |
| 1-phenylimidazole | 1-phenylimidazole: ligand for cytochrome P-450 & inhibitor of microsomal oxidation | ||
| 3-indazolinone | 3-indazolinone: structure given in first source | ||
| 5-aminoindazole | |||
| 3,5-dimethylpyrazole-1-carboxamidine | 3,5-dimethylpyrazole-1-carboxamidine: guanidinating reagent for proteins; RN given refers to parent cpd | ||
| s-methylthiocitrulline | S-methyl-L-thiocitrulline : An L-arginine derivative in which the guanidino NH2 group of L-arginine is replaced by a methylsufanyl group. S-methylthiocitrulline: a nitric oxide synthase inhibitor; structure in first source | imidothiocarbamic ester; L-arginine derivative; L-ornithine derivative; non-proteinogenic L-alpha-amino acid | EC 1.14.13.39 (nitric oxide synthase) inhibitor; neuroprotective agent |
| n(g)-iminoethylornithine | L-alpha-amino acid | ||
| n,n-dimethylarginine | N,N-dimethylarginine: asymmetric dimethylarginine; do not confuse with N,N'-dimethylarginine N(omega),N(omega)-dimethyl-L-arginine : A L-arginine derivative having two methyl groups both attached to the primary amino moiety of the guanidino group. | dimethylarginine; guanidines; L-arginine derivative; non-proteinogenic L-alpha-amino acid | EC 1.14.13.39 (nitric oxide synthase) inhibitor |
| n(omega)-hydroxyarginine | N(5)-[(Z)-amino(hydroxyimino)methyl]-L-ornithine : An N(5)-[amino(hydroxyimino)methyl]-L-ornithine in which the double bond has Z-configuration. N(omega)-hydroxyarginine: can cause vasorelaxation of bovine intrapulmonary artery; structure given in first source | amino acid zwitterion; N(5)-[(E)-amino(hydroxyimino)methyl]ornithine; N(5)-[(hydroxyamino)(imino)methyl]ornithine; N(5)-[(Z)-amino(hydroxyimino)methyl]ornithine; N(5)-[amino(hydroxyimino)methyl]-L-ornithine; N(5)-[amino(hydroxyimino)methyl]ornithine; N(omega)-hydroxy-L-arginine | |
| omega-n-methylarginine | N(omega)-methyl-L-arginine : A L-arginine derivative with a N(omega)-methyl substituent. omega-N-Methylarginine: A competitive inhibitor of nitric oxide synthetase. | amino acid zwitterion; arginine derivative; guanidines; L-arginine derivative; non-proteinogenic L-alpha-amino acid | |
| ng-nitroarginine methyl ester | N(gamma)-nitro-L-arginine methyl ester hydrochloride : A hydrochloride obtained by combining N(gamma)-nitro-L-arginine methyl ester with one equivalent of hydrochloric acid. | hydrochloride | EC 1.14.13.39 (nitric oxide synthase) inhibitor |
| n-n-propylnorapomorphine | aporphine alkaloid | ||
| delta-n-methylarginine | N(5)-methyl-L-arginine : A non-proteinogenic L-alpha-amino acid that is L-arginine substituted by a methyl group at N(5)-position. | guanidines; L-arginine derivative; non-proteinogenic L-alpha-amino acid | |
| 2-amino-5,6-dihydro-4h-1,3-thiazine | 2-amino-5,6-dihydro-4H-1,3-thiazine: RN given refers to parent cpd | ||
| 2-amino-5-methylthiazole | 2-amino-5-methylthiazole: binds the W191G cavity of E coli cytochrome c peroxidase | ||
| Bardoxolone | cyclohexenones | ||
| canavanine | L-canavanine : A non-proteinogenic L-alpha-amino acid that is L-homoserine substituted at oxygen with a guanidino (carbamimidamido) group. Although structurally related to L-arginine, it is non-proteinogenic. | amino acid zwitterion; non-proteinogenic L-alpha-amino acid | phytogenic insecticide; plant metabolite |
| monoiodotyrosine | 3-iodo-L-tyrosine : The monoiodotyrosine that is L-tyrosine carrying an iodo-substituent at position C-3 of the benzyl group. iodotyrosine : A tyrosine derivative which has at least one iodo-substituent on the benzyl moiety. monoiodotyrosine : An iodotyrosine carrying a single iodo substituent. Monoiodotyrosine: A product from the iodination of tyrosine. In the biosynthesis of thyroid hormones (THYROXINE and TRIIODOTHYRONINE), tyrosine is first iodized to monoiodotyrosine. | amino acid zwitterion; L-tyrosine derivative; monoiodotyrosine; non-proteinogenic L-alpha-amino acid | EC 1.14.16.2 (tyrosine 3-monooxygenase) inhibitor; human metabolite; mouse metabolite |
| nitroarginine | N(gamma)-nitro-L-arginine : An L-arginine derivative that is L-arginine in which the terminal nitrogen of the guanidyl group is replaced by a nitro group. Nitroarginine: An inhibitor of nitric oxide synthetase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. (Neurochem Res 1995:200(4):451-6) | guanidines; L-arginine derivative; N-nitro compound; non-proteinogenic L-alpha-amino acid | |
| vinyl-l-nio | |||
| arl 17477 | |||
| n(6)-(1-iminoethyl)lysine | N(6)-acetimidoyl-L-lysine : An L-lysine derivative that is L-lysine in which one of the hydrogens attached to N(6) is substituted by an acetimidoyl group | L-lysine derivative; non-proteinogenic L-alpha-amino acid | |
| pyrazole-1-carboxamidine | pyrazole-1-carboxamidine: structure given in first source | ||
| gw 274150 | |||
| aq4n | AQ4N: structure given in first source | ||
| 11-hydroxy-n-(n-propyl)noraporphine hydrochloride, (r)-isomer | |||
| oleanonic acid | oleanonic acid: structure in first source | ||
| n-trans-p-coumaroyl-l-tyrosine | N-trans-p-coumaroyl-L-tyrosine: from Theobroma cacao; structure in first source | tyrosine derivative | |
| 1-(4-(3-bromophenoxy)butyl)-1h-imidazole | 1-(4-(3-bromophenoxy)butyl)-1H-imidazole: structure in first source | ||
| sapropterin | (6R)-5,6,7,8-tetrahydrobiopterin : A 5,6,7,8-tetrahydrobiopterin in which the stereocentre at position 6 has R-configuration. sapropterin : A tetrahydropterin that is 2-amino-5,6,7,8-tetrahydropteridin-4(3H)-one in which a hydrogen at position 6 is substituted by a 1,2-dihydroxypropyl group (6R,1'R,2'S-enantiomer). sapropterin: RN given refers to parent cpd; co-factor required for catalytic activity of nitric oxide synthases | 5,6,7,8-tetrahydrobiopterin | coenzyme; cofactor; diagnostic agent; human metabolite |
| 6-hydroxymethylpterin |