title: Hydrolysis of S-aryl-cysteinylglycine conjugates catalyzed by porcine kidney cortex membrane dipeptidase.
abstract: Following conjugation with glutathione, xenobiotics are converted into cysteinylglycine conjugates, cysteine conjugates, and finally, mercapturic acids. The structural factors determining the activities of dipeptidases for the metabolism of toxicologically-relevant cysteinylglycine conjugates are not well understood.        We purified porcine kidney cortex membrane dipeptidase (MDP) to homogeneity, via phosphatidylinositol-specific phospholipase C-mediated cleavage of the protein's membrane anchor and cilastatin affinity chromatography. The homodimeric structure of the MDP protein was confirmed by mass spectrometry.        The cysteinylglycine conjugates of 1-(chloromethyl)naphthalene, 4-nitrobenzyl chloride, and 1-chloro-2,4-dinitrobenzene were synthesized and HPLC separation methods for their quantitation were developed. MDP catalyzed the hydrolysis of all three conjugates, but the rate of this activity was strongly dependent on the nature of the substituent on the cysteine sulfur atom.
authors: Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario \, Canada.
authors: James C H
authors: JC
authors: Poon
authors: P David
authors: PD
authors: Josephy
mesh_terms: D000818:Animals; D055162:Biocatalysis; D003545:Cysteine / Q000378:metabolism; D004150:Dipeptidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005978:Glutathione / Q000378:metabolism; D006868:Hydrolysis; D007672:Kidney Cortex / Q000201:enzymology*; D007700:Kinetics; D008566:Membranes / Q000201:enzymology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D034421:Sus scrofa / Q000378:metabolism*
chemical_list: D004151:Dipeptides; C028505:cysteinylglycine; D004150:Dipeptidases; C038937:dipeptidase; D005978:Glutathione; D003545:Cysteine