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Mercapturic acids are condensation products formed from the coupling of cysteine with aromatic compounds.[1] They are formed as conjugates in the liver and are excreted in the urine.[1]
Mercapturic acids are formed as part of xenobiotic metabolism. A glutathione S-transferase first conjugates the foreign compound to glutathione, forming an adduct. The adduct is then converted to the mercapturic acid: the γ-glutamate and glycine residues in the glutathione molecule are removed by Gamma-glutamyl transpeptidase and dipeptidases. In the final step, the cystine residue in the conjugate is acetylated. The mercapturic acid is then excreted.[2]
Levels of mercapturic acids in urine may be used as an indicator of exposure to, e.g., ethylene dibromide,[3] acrylamide, and terbuthylazine.[4]
Etymology
editThe name "mercapturic acid" is a combination of "mercapturic" and "acid". The latter indicates that the compound is an acid. The former is a compound word consisting of the stem "mercaptur-", coming from "mercaptan", and the suffix "-ic", meaning "having the character of". In sum, the name "mercapturic acid" means "an acid with mercaptan character/nature".[5]
References
edit- ^ a b medical-dictionary.thefreedictionary.com Retrieved on June 25, 2009
- ^ Boyland E, Chasseaud LF (1969). "The Role of Glutathione and Glutathione S-Transferases in Mercapturic Acid Biosynthesis". Advances in Enzymology and Related Areas of Molecular Biology. Advances in Enzymology - and Related Areas of Molecular Biology. Vol. 32. pp. 173–219. doi:10.1002/9780470122778.ch5. ISBN 978-0-470-64961-9. PMID 4892500.
{{cite book}}:|journal=ignored (help) - ^ Kim DH, Guengerich FP (November 1989). "Excretion of the mercapturic acid S-[2-(N7-guanyl)ethyl]-N-acetylcysteine in urine following administration of ethylene dibromide to rats". Cancer Res. 49 (21): 5843–7. PMID 2790795.
- ^ Mercadante R, Polledri E, Fustinoni S (July 2012). "Determination of terbuthylazine and desethylterbuthylazine in human urine and hair samples by eletrospray ionization-liquid chromatography/triple quadrupole mass spectrometry". Analytical and Bioanalytical Chemistry. 404 (3): 875–86. doi:10.1007/s00216-012-6184-3. PMID 22752446. S2CID 2087135.
- ^ "Definition of IC". www.merriam-webster.com. 2024-03-26. Retrieved 2024-04-27.
Further reading
edit- Hanna, Patrick E.; Anders, M. W. (26 November 2019). "The mercapturic acid pathway". Critical Reviews in Toxicology. 49 (10): 819–929. doi:10.1080/10408444.2019.1692191.
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