Target type: biologicalprocess
Any process that modulates the frequency, rate or extent of cardiac muscle contraction by changing the calcium ion signals that trigger contraction. [GOC:BHF, GOC:dph, GOC:tb]
Cardiac muscle contraction is a precisely regulated process driven by the intricate interplay of calcium ion signaling. The process begins with an action potential traveling down the sarcolemma, the muscle cell membrane. This electrical signal reaches the T-tubules, invaginations of the sarcolemma that extend into the muscle fiber, triggering the release of calcium ions from the sarcoplasmic reticulum (SR). The SR is an intracellular calcium store analogous to the endoplasmic reticulum in other cell types.
Calcium ions bind to troponin C, a component of the troponin complex, which is bound to tropomyosin, a filamentous protein that wraps around the actin filaments of the sarcomere, the fundamental contractile unit of muscle. This binding causes a conformational change in troponin, moving tropomyosin away from the myosin binding sites on the actin filament. With these sites now exposed, myosin heads, which are bound to ATP, can bind to actin, initiating the cross-bridge cycle.
The cross-bridge cycle involves the following steps:
1. **Attachment:** The myosin head, bound to ADP and inorganic phosphate, attaches to the actin filament.
2. **Power Stroke:** The myosin head releases inorganic phosphate and undergoes a conformational change, pulling the actin filament towards the center of the sarcomere, generating force and shortening the muscle fiber.
3. **Detachment:** ATP binds to the myosin head, causing it to detach from actin.
4. **Reactivation:** ATP is hydrolyzed to ADP and inorganic phosphate, re-energizing the myosin head, and the cycle repeats as long as calcium is bound to troponin.
As the action potential subsides, calcium ions are actively pumped back into the SR by a calcium ATPase, a membrane-bound protein. This decrease in cytoplasmic calcium concentration allows tropomyosin to cover the myosin binding sites on actin, inhibiting further cross-bridge formation, and causing muscle relaxation.
The regulation of calcium ion concentration in the cytoplasm of cardiac muscle cells is essential for proper muscle function. Abnormalities in this signaling pathway can lead to impaired contractility and various cardiovascular diseases.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Sarcoplasmic/endoplasmic reticulum calcium ATPase 2 | A sarcoplasmic/endoplasmic reticulum calcium ATPase 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P16615] | Homo sapiens (human) |
| Ryanodine receptor 2 | A ryanodine receptor 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q92736] | 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) |
| Sodium/hydrogen exchanger 1 | A sodium/hydrogen exchanger 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P19634] | Homo sapiens (human) |
| Sodium/potassium-transporting ATPase subunit beta-1 | A sodium/potassium-transporting ATPase subunit beta-1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P05026] | 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 | |||
| ethylisopropylamiloride | ethylisopropylamiloride : A member of the class of pyrazines that is amiloride in which the amino substitutent of the pyrazine ring that is adjacent to the chloro substituent has been substituted by an ethyl group and by an isopropyl group. ethylisopropylamiloride: structure in first source | aromatic amine; guanidines; monocarboxylic acid amide; organochlorine compound; pyrazines; tertiary amino compound | anti-arrhythmia drug; neuroprotective agent; sodium channel blocker |
| 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 | |
| 2,5-di-tert-butylhydroquinone | 2,5-di-tert-butylbenzene-1,4-diol : A member of the class of hydroquinones that is benzene-1,4-diol substituted by tert-butyl groups at position 2 and 5. | hydroquinones | |
| s-ethyl n-(4-(trifluoromethyl)phenyl)isothiourea | S-ethyl N-(4-(trifluoromethyl)phenyl)isothiourea: structure in first source | ||
| lansoprazole | Lansoprazole: A 2,2,2-trifluoroethoxypyridyl derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS. Lansoprazole is a racemic mixture of (R)- and (S)-isomers. | benzimidazoles; pyridines; sulfoxide | anti-ulcer drug; EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor |
| omeprazole | 5-methoxy-2-{[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl}-1H-benzimidazole : A member of the class of benzimidazoles that is 1H-benzimidazole which is substituted by a [4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl group at position 2 and a methoxy group at position 5. omeprazole : A racemate comprising equimolar amounts of (R)- and (S)-omeprazole. Omeprazole: A 4-methoxy-3,5-dimethylpyridyl, 5-methoxybenzimidazole derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits an H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS. | aromatic ether; benzimidazoles; pyridines; sulfoxide | |
| pantoprazole | pantoprazole : A member of the class of benzimidazoles that is 1H-benzimidazole substituted by a difluoromethoxy group at position 5 and a [(3,4-dimethoxypyridin-2-yl)methyl]sulfinyl group at position 2. Pantoprazole: 2-pyridinylmethylsulfinylbenzimidazole proton pump inhibitor that is used in the treatment of GASTROESOPHAGEAL REFLUX and PEPTIC ULCER. | aromatic ether; benzimidazoles; organofluorine compound; pyridines; sulfoxide | anti-ulcer drug; EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor; environmental contaminant; xenobiotic |
| 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 |
| benzotriazole | benzotriazole : The simplest member of the class of benzotriazoles that consists of a benzene nucleus fused to a 1H-1,2,3-triazole ring. benzotriazole: inhibitor of atmospheric metal corrosion; also component of motion picture film & Neva brake fluid | benzotriazoles | environmental contaminant; xenobiotic |
| 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. | ||
| 2-amino-3-methylpyridine | 2-amino-3-methylpyridine: structure in first source | ||
| digoxigenin | digoxigenin : A hydroxy steroid that consists of 5beta-cardanolide having a double bond at the 20(22)-position as well as hydroxy groups at the 3beta-, 12beta- and 14beta-positions. It has been isolated from the plant species of the genus Digitalis. Digoxigenin: 3 beta,12 beta,14-Trihydroxy-5 beta-card-20(22)-enolide. A cardenolide which is the aglycon of digoxin. Can be obtained by hydrolysis of digoxin or from Digitalis orientalis L. and Digitalis lanata Ehrh. | 12beta-hydroxy steroid; 14beta-hydroxy steroid; 3beta-hydroxy steroid; 3beta-sterol | hapten; plant metabolite |
| 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 | |
| amiloride | amiloride : A member of the class of pyrazines resulting from the formal monoacylation of guanidine with the carboxy group of 3,5-diamino-6-chloropyrazine-2-carboxylic acid. Amiloride: A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705) | aromatic amine; guanidines; organochlorine compound; pyrazines | diuretic; sodium channel blocker |
| 5-nitroindazole | |||
| 6-nitroindazole | |||
| 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 | ||
| amiloride hydrochloride | amiloride hydrochloride dihydrate : A hydrate that is the dihydrate of amiloride hydrochloride. | hydrate | diuretic; sodium channel blocker |
| 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 | |||
| digoxigenin-bis(digitoxoside) | cardenolide glycoside | ||
| 3,5-dimethylpyrazole-1-carboxamidine | 3,5-dimethylpyrazole-1-carboxamidine: guanidinating reagent for proteins; RN given refers to parent cpd | ||
| paxilline | paxilline : An indole diterpene alkaloid with formula C27H33NO4 isolated from Penicillium paxilli. It is a potent inhibitor of large conductance Ca2(+)- and voltage-activated K(+) (BK)-type channels. paxilline: structure given in first source; RN given refers to (2R-(2alpha,4bbeta,6aalpha,12bbeta,12calpha,14abeta))-isomer | diterpene alkaloid; enone; organic heterohexacyclic compound; terpenoid indole alkaloid; tertiary alcohol | anticonvulsant; Aspergillus metabolite; EC 3.6.3.8 (Ca(2+)-transporting ATPase) inhibitor; genotoxin; geroprotector; mycotoxin; Penicillium metabolite; potassium channel blocker |
| 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 |
| 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 |
| cariporide | cariporide: a selective sodium-hydrogen exchange subtype 1 inhibitor; structure in first source | ||
| rostafuroxin | rostafuroxin: structure in first source | ||
| 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 | ||
| ouabain | cardiac glycoside : Steroid lactones containing sugar residues that act on the contractile force of the cardiac muscles. ouabain : A steroid hormone that is a multi-hydroxylated alpha-L-rhamnosyl cardenoloide. It binds to and inhibits the plasma membrane Na(+)/K(+)-ATPase (sodium pump). It has been isolated naturally from Strophanthus gratus. Ouabain: A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE. | 11alpha-hydroxy steroid; 14beta-hydroxy steroid; 5beta-hydroxy steroid; alpha-L-rhamnoside; cardenolide glycoside; steroid hormone | anti-arrhythmia drug; cardiotonic drug; EC 2.3.3.1 [citrate (Si)-synthase] inhibitor; EC 3.1.3.41 (4-nitrophenylphosphatase) inhibitor; EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor; EC 3.6.3.9 (Na(+)/K(+)-transporting ATPase) inhibitor; ion transport inhibitor; plant 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 | |
| digitoxin | digitoxin : A cardenolide glycoside in which the 3beta-hydroxy group of digitoxigenin carries a 2,6-dideoxy-beta-D-ribo-hexopyranosyl-(1->4)-2,6-dideoxy-beta-D-ribo-hexopyranosyl-(1->4)-2,6-dideoxy-beta-D-ribo-hexopyranosyl trisaccharide chain. Digitoxin: A cardiac glycoside sometimes used in place of DIGOXIN. It has a longer half-life than digoxin; toxic effects, which are similar to those of digoxin, are longer lasting. (From Martindale, The Extra Pharmacopoeia, 30th ed, p665) | cardenolide glycoside | EC 3.6.3.9 (Na(+)/K(+)-transporting ATPase) inhibitor |
| vinyl-l-nio | |||
| arl 17477 | |||
| curcumin | curcumin : A beta-diketone that is methane in which two of the hydrogens are substituted by feruloyl groups. A natural dyestuff found in the root of Curcuma longa. Curcumin: A yellow-orange dye obtained from tumeric, the powdered root of CURCUMA longa. It is used in the preparation of curcuma paper and the detection of boron. Curcumin appears to possess a spectrum of pharmacological properties, due primarily to its inhibitory effects on metabolic enzymes. | aromatic ether; beta-diketone; diarylheptanoid; enone; polyphenol | anti-inflammatory agent; antifungal agent; antineoplastic agent; biological pigment; contraceptive drug; dye; EC 1.1.1.205 (IMP dehydrogenase) inhibitor; EC 1.1.1.21 (aldehyde reductase) inhibitor; EC 1.1.1.25 (shikimate dehydrogenase) inhibitor; EC 1.6.5.2 [NAD(P)H dehydrogenase (quinone)] inhibitor; EC 1.8.1.9 (thioredoxin reductase) inhibitor; EC 2.7.10.2 (non-specific protein-tyrosine kinase) inhibitor; EC 3.5.1.98 (histone deacetylase) inhibitor; flavouring agent; food colouring; geroprotector; hepatoprotective agent; immunomodulator; iron chelator; ligand; lipoxygenase inhibitor; metabolite; neuroprotective agent; nutraceutical; radical scavenger |
| digoxin | digoxin : A cardenolide glycoside that is digitoxin beta-hydroxylated at C-12. A cardiac glycoside extracted from the foxglove plant, Digitalis lanata, it is used to control ventricular rate in atrial fibrillation and in the management of congestive heart failure with atrial fibrillation, but the margin between toxic and therapeutic doses is small. Digoxin: A cardiotonic glycoside obtained mainly from Digitalis lanata; it consists of three sugars and the aglycone DIGOXIGENIN. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in ATRIAL FIBRILLATION and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. (From Martindale, The Extra Pharmacopoeia, 30th ed, p666) | cardenolide glycoside; steroid saponin | anti-arrhythmia drug; cardiotonic drug; EC 3.6.3.9 (Na(+)/K(+)-transporting ATPase) inhibitor; epitope |
| 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 | ||
| digitoxigenin | digitoxigenin : A 5beta-cardenolide that is 5beta-cardanolide with hydroxy substituents at the 3beta- and 14beta-positions and double bond unsaturation at C(20)-C(22). Digitoxigenin: 3 beta,14-Dihydroxy-5 beta-card-20(22)enolide. A cardenolide which is the aglycon of digitoxin. Synonyms: Cerberigenin; Echujetin; Evonogenin; Thevetigenin. | 14beta-hydroxy steroid; 3beta-hydroxy steroid | |
| eniporide | eniporide: inhibits NHE-1 isoform; structure in first source | ||
| zoniporide | zoniporide: inhibits sodium-hydrogen exchanger isoform-1 (NHE-1) | ||
| gw 274150 | |||
| sabiporide | sabiporide: a NHE-1 inhibitor and a cardioprotective agent; structure in first source | ||
| phakellistatin 2 | phakellistatin 2: isolated from the marine sponge Phakellia carteri; structure in first source | ||
| chlorantranilipole | chlorantranilipole: anthranilic diamide insecticide.that disrupts mating in codling moth (Lepidoptera: Tortricidae) chlorantraniliprole : A carboxamide resulting from the formal condensation of the carboxylic acid group of 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid with the primary amino group of 2-amino-5-chloro-N,3-dimethylbenzamide. The first of the anthranilic diamide insecticides, it is a ryanodine receptor activator and is used to protect a wide variety of crops, including corn, cotton, grapes, rice and potatoes. | monochlorobenzenes; organobromine compound; pyrazole insecticide; pyrazoles; pyridines; secondary carboxamide | ryanodine receptor agonist |
| (5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl)guanidine | (5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl)guanidine: KR-32570 possesses potent cardioprotective effects in perfused rat hearts, and its effects may be mediated by inhibition of NHE-1, preservation of high-energy phosphates, and inhibition of lipid peroxidation | ||
| digitoxigenin monodigitoxoside | digitoxigenin monodigitoxoside: RN given refers to (ribo-3beta,5beta)-isomer | ||
| evomonoside | evomonoside : A cardenolide glycoside consisting of digitoxigenin having an alpha-L-rhamnosyl moiety attached at the O(3)-position. evomonoside: a cytotoxic cardiac glycoside from Lepidium apetalum; RN refers to (3beta,5beta)-isomer | cardenolide glycoside | |
| halisulfate 1 | halisulfate 1: an isocitrate lyase inhibitor sesterterpene sulfate from sponge, Hippospongia sp.; structure in first source | organic molecular entity | metabolite |
| biselyngbyaside | biselyngbyaside: antineoplastic from the marine cyanobacterium Lyngbya sp.; structure in first source | ||
| 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 | |||
| alpha-cyclopiazonic acid | alpha-cyclopiazonic acids |