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Formula | C12H15NO3S |
Molar mass | 253.32 g·mol−1 |
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Chirality | Racemic mixture |
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Thiorphan is the active metabolite of the antidiarrheal racecadotril (acetorphan). [1] It prevents the degradation of endogenous enkephalins by acting as an enkephalinase inhibitor. [1] [2]
An enkephalin is a pentapeptide involved in regulating nociception in the body. The enkephalins are termed endogenous ligands, as they are internally derived and bind to the body's opioid receptors. Discovered in 1975, two forms of enkephalin have been found, one containing leucine ("leu"), and the other containing methionine ("met"). Both are products of the proenkephalin gene.
Opioid peptides or opiate peptides are peptides that bind to opioid receptors in the brain; opiates and opioids mimic the effect of these peptides. Such peptides may be produced by the body itself, for example endorphins. The effects of these peptides vary, but they all resemble those of opiates. Brain opioid peptide systems are known to play an important role in motivation, emotion, attachment behaviour, the response to stress and pain, control of food intake, and the rewarding effects of alcohol and nicotine.
Opiorphin is an endogenous chemical compound first isolated from human saliva. Initial research with mice shows the compound has a painkilling effect greater than that of morphine. It works by stopping the normal breakup of enkephalins, natural pain-killing opioids in the spinal cord. It is a relatively simple molecule consisting of a five-amino acid polypeptide, Gln-Arg-Phe-Ser-Arg (QRFSR).
Met-enkephalin, also known as metenkefalin (INN), sometimes referred to as opioid growth factor (OGF), is a naturally occurring, endogenous opioid peptide that has opioid effects of a relatively short duration. It is one of the two forms of enkephalin, the other being leu-enkephalin. The enkephalins are considered to be the primary endogenous ligands of the δ-opioid receptor, due to their high potency and selectivity for the site over the other endogenous opioids.
Neprilysin, also known as membrane metallo-endopeptidase (MME), neutral endopeptidase (NEP), cluster of differentiation 10 (CD10), and common acute lymphoblastic leukemia antigen (CALLA) is an enzyme that in humans is encoded by the MME gene. Neprilysin is a zinc-dependent metalloprotease that cleaves peptides at the amino side of hydrophobic residues and inactivates several peptide hormones including glucagon, enkephalins, substance P, neurotensin, oxytocin, and bradykinin. It also degrades the amyloid beta peptide whose abnormal folding and aggregation in neural tissue has been implicated as a cause of Alzheimer's disease. Synthesized as a membrane-bound protein, the neprilysin ectodomain is released into the extracellular domain after it has been transported from the Golgi apparatus to the cell surface.
The ∆-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi/G0 and has enkephalins as its endogenous ligands. The regions of the brain where the ∆-opioid receptor is largely expressed vary from species model to species model. In humans, the ∆-opioid receptor is most heavily expressed in the basal ganglia and neocortical regions of the brain.
Racecadotril, also known as acetorphan, is an antidiarrheal medication which acts as a peripheral enkephalinase inhibitor. Unlike other opioid medications used to treat diarrhea, which reduce intestinal motility, racecadotril has an antisecretory effect — it reduces the secretion of water and electrolytes into the intestine. It is available in France and other European countries as well as most of South America and some South East Asian countries, but not in the United States. It is sold under the tradename Hidrasec, among others. Thiorphan is the active metabolite of racecadotril, which exerts the bulk of its inhibitory actions on enkephalinases.
RB-101 is a drug that acts as an enkephalinase inhibitor, which is used in scientific research.
The molecular formula C21H23NO4S (molar mass: 385.48 g/mol, exact mass: 385.1348 u) may refer to:
Enkephalinases are enzymes that degrade endogenous enkephalin opioid peptides. They include:
Ecadotril is a neutral endopeptidase inhibitor ((NEP) EC 3.4.24.11) and determined by the presence of peptidase family M13 as a neutral endopeptidase inhibited by phosphoramidon. Ecadotril is the (S)-enantiomer of racecadotril. NEP-like enzymes include the endothelin-converting enzymes. The peptidase M13 family believed to activate or inactivate oligopeptide (pro)-hormones such as opioid peptides, neprilysin is another member of this group, in the case of the metallopeptidases and aspartic, the nucleophiles clan or family for example MA, is an activated water molecule. The peptidase domain for members of this family also contains a bacterial member and resembles that of thermolysin the predicted active site residues for members of this family and thermolysin occur in the motif HEXXH. Thermolysin complexed with the inhibitor (S)-thiorphan are isomeric thiol-containing inhibitors of endopeptidase EC 24-11 (also called "enkephalinase").
Kelatorphan is a drug which acts as a powerful and complete inhibitor of nearly all of the enzymes responsible for catabolism of the endogenous enkephalins, including neutral endopeptidase (NEP), dipeptidyl peptidase III (DPP3), aminopeptidase N (APN), and angiotensin-converting enzyme (ACE). In mice, with the intracerebroventricular co-administration of a 50 µg dose of kelatorphan (this route is necessary because kelatorphan is incapable of crossing the blood-brain-barrier) hence alongside exogenous [Met]enkephalin (ED50 approximately 10 ng), it potentiated the analgesic effects of the latter by 50,000 times. Kelatorphan also displays potent antinociceptive effects alone, and does not depress respiration, although at high doses it actually increases it.
An enkephalinase inhibitor is a type of enzyme inhibitor which inhibits one or more members of the enkephalinase class of enzymes that break down the endogenous enkephalin opioid peptides. Examples include racecadotril, ubenimex (bestatin), RB-101, and D-phenylalanine, as well as the endogenous opioid peptides opiorphin and spinorphin. It also includes RB-3007, Semax and Selank. Analgesic, anticraving, antidepressant, anxiolytic, and antidiarrheal effects are common properties of enkephalinase inhibitors.
Spinorphin is an endogenous, non-classical opioid peptide of the hemorphin family first isolated from the bovine spinal cord (hence the prefix spin-) and acts as a regulator of the enkephalinases, a class of enzymes that break down endogenous the enkephalin peptides. It does so by inhibiting the enzymes aminopeptidase N (APN), dipeptidyl peptidase III (DPP3), angiotensin-converting enzyme (ACE), and neutral endopeptidase (NEP). Spinorphin is a heptapeptide and has the amino acid sequence Leu-Val-Val-Tyr-Pro-Trp-Thr (LVVYPWT). It has been observed to possess antinociceptive, antiallodynic, and anti-inflammatory properties. The mechanism of action of spinorphin has not been fully elucidated (i.e., how it acts to inhibit the enkephalinases), but it has been found to act as an antagonist of the P2X3 receptor, and as a weak partial agonist/antagonist of the FP1 receptor.
Tynorphin is a synthetic opioid peptide which is a potent and competitive inhibitor of the enkephalinase class of enzymes which break down the endogenous enkephalin peptides. It specifically inactivates dipeptidyl aminopeptidase III (DPP3) with very high efficacy, but also inhibits neutral endopeptidase (NEP), aminopeptidase N (APN), and angiotensin-converting enzyme (ACE) to a lesser extent. It has a pentapeptide structure with the amino acid sequence Val-Val-Tyr-Pro-Trp (VVYPW).
Jean-Charles Schwartz, born on May 28, 1936, in Paris, is a French neurobiologist, pharmacist and researcher. Husband of Ketty Schwartz, née Gersen (1937-2007) and father of Olivier, Marc and Emmanuelle. He is a member of the Academy of Sciences.. He developed pitolisant, the first clinically approved antagonist for H3 receptors.
Oxytocinase is a type of enzyme that metabolizes the endogenous neuropeptide, oxytocin. The most well-characterized oxytocinase is leucyl/cystinyl aminopeptidase, which is also an enkephalinase. Other oxytocinases are also known. During pregnancy, oxytocinase plays a role in balancing concentration of oxytocin by degrading the oxytocin produced by the fetus, as production of oxytocin increases with growth of fetus. One study found that concentration level of oxytocinase increased progressively with gestational age until labor, which indicates that pregnancy development can be statistically evaluated by comparing oxytocinase levels.
An endopeptidase inhibitor is a drug that inhibits one or more endopeptidase enzymes. Endopeptidases are one of two types of proteases, the other being exopeptidases. Endopeptidases cleave peptide bonds of non-terminal amino acids, whereas exopeptidases break terminal bonds, resulting in the release of a single amino acid or dipeptide from the peptide chain.
An exopeptidase inhibitor is a drug that inhibits one or more exopeptidase enzymes. Exopeptidases are one of two types of proteases, the other being endopeptidases. Exopeptidases cleave peptide bonds of terminal amino acids, resulting in the release of a single amino acid or dipeptide from the peptide chain, whereas endoeptidases break non-terminal bonds.
RB-3007 is an orally active analogue of RB-101. It acts as an enkephalinase inhibitor, which is used in scientific research.