Title: Chromatographic resolution of amino acid adducts of aliphatic halides.

Authors: Maiorino, R M; Gandolfi, A J; Brendel, K; Mac Donald, J R; Sipes, I G

Published In Chem Biol Interact, (1982 Jan)

Abstract: Numerous xenobiotics are known to be bioactivated and to covalently and to proteins, but the resulting amino acid adducts (AAAs) are unknown. In this study the AAAs of twelve 14C-labeled aliphatic halides were examined after formation in an in vitro microsomal system. After exhaustive solvent extraction of the precipitated microsomal protein, the AAAs were isolated by Pronase digestion, followed by filtration through a 500 mol. wt. exclusion membrane. The liberated AAAs were applied to a constant flow DC-4A cation exchange column, resolved by stepwise buffer elution, collected and counted for radioactivity. Column recovery for applied radioactivity was 100 +/- 4%. Generally, 1-4 different AAAs (defined by eluting radioactivity) were resolved, with each organohalogen displaying a characteristic elution profile. Methyl iodide, trichloroethylene and 1,2-dichloroethylene had a single major AAA while bromotrichloromethane, 1,2-dibromoethane, 1,1,1-trichloroethane, 1,2-dichloroethane, 1,1,2-trichloroethane, 2-bromo-2-chloro-1,1,1-trifluoroethane, chloroform and carbon tetrachloride had up to 4 AAAs or more, indicating combinations of binding site(s) and reactive intermediate(s). The single AAA formed following incubation of methyl iodide with the microsomes was identified as S-methylcysteine. Thus, this method appears capable of resolving binding sites and is the initial isolation step for identifying specific adducts to proteins.

PubMed ID: 7055850

MeSH Terms: Amino Acids/metabolism*; Animals; Biotransformation; Chromatography, Ion Exchange; Gas Chromatography-Mass Spectrometry; Hydrocarbons, Halogenated/metabolism*; Male; Microsomes, Liver/metabolism; Rats; Rats, Inbred Strains