title: 5-S-cysteinyldopac in human urine.
abstract: 5-S-Cysteinyldopac, a compound hitherto demonstrated only in brain tissue, has been isolated and quantified in urine. The urines from 12 individuals were found to contain 20 +/- 9.1 micrograms 5-S-cysteinyldopac/24 hours. Incubation of 5-S-cysteinyldopamine with MAO-containing tissue did not give any formation of 5-S-cysteinyldopac, indicating that this compound is formed by nucleophilic addition of cysteine directly to dopac. The findings give further evidence for a small but significant non-specific oxidation of endogenous catechol derivatives in vivo, a fact to be considered when using 5-S-cysteinyldopa as a measure of pigment metabolism.
authors.affiliation: Department of Dermatology, University of Lund, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Carstam
authors.forename: C
authors.initials: C
authors.lastname: Brinck
authors.forename: B
authors.initials: B
authors.lastname: Fornstedt
authors.forename: H
authors.initials: H
authors.lastname: Rorsman
authors.forename: E
authors.initials: E
authors.lastname: Rosengren
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism / Q000652:urine; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003548:Cysteinyldopa / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D010084:Oxidation-Reduction
chemical_list: D015102:3,4-Dihydroxyphenylacetic Acid; C049277:5-S-cysteinyl-3,4-dihydroxyphenylacetic acid; D003548:Cysteinyldopa