Methylmercury(II) sulfhydryl interactions. Potentiometric determination of the formation constants for complexation of methylmercury(II) by sulfhydryl containing amino acids and related molecules, including glutathione

The interaction of methylmercury with thiols to form methylmercury thiolate complexes MeHgSR is believed to be important in both the toxicology of methylmercury and the use of antidotes for mercury poisoning containing thiol groups. Thus, a fundamental requirement in studying the biological behaviour of methylmercury is accurate values of equilibrium constants for these interactions. Formation constants for the interaction of mcthylmercury(II) with 2-mercaptoethanol. mercaptoacetic acid. O-methylmercaptoacetate. 2-mercaptosuccinic acid. L-cystcinc, D,L-penicillamine. N-acetyl-D,L-penicillamine, glutathione, thiocholine. and 4-mercapto-N-methylpiperidine have been dctcnnincd by potentiometric titratiun. Acid dissociation constants for the ligands are reported. Formation constants for the addition of both one and two equivalents of methylmercury to L-cysteine have been determined.