title: Synthesis of 5-S-L-cysteinyl-glycine-L-dopa, a natural substrate for serum and melanocyte dipeptidase.
abstract: A method for synthesis of the phaeomelanin pigment intermediate compound 5-S-L-cysteinyl-glycine-L-dopa is presented. This thioether has been suggested as a precursor to 5-S-L-cysteinyl-L-dopa, the key intermediate compound in phaeomelanin pigment formation. 5-S-Glutathione-L-dopa is first synthesized by the tyrosinase-catalyzed reaction between L-dopa and glutathione. The 5-S-glutathione-L-dopa is then converted to 5-S-L-cysteinyl-glycine-L-dopa using the enzyme gamma-glutamyl transpeptidase. The compound thus obtained was suitable as a substrate for melanoma cell and serum dipeptidase which converts the compound into 5-S-L-cysteinyl-L-dopa and glycine. The optimum pH for the dipeptidase from melanoma cells was 7.5 and the Km was 1.2 mM.
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003548:Cysteinyldopa / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D004150:Dipeptidases / Q000097:blood / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008544:Melanocytes / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: C054310:5-S-cysteinyl-glycyl-dopa; D003548:Cysteinyldopa; D004295:Dihydroxyphenylalanine; D004150:Dipeptidases