Nuclear Magnetic Resonance Studies of the Solution Chemistry of

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Nuclear Magnetic Resonance Studies of the Solution Chemistry of Metal Complexes. XI. The Binding of Methylmercury by Sulfhydryl-Containing Amino Acids and by Glutathione' Dallas L. Rabenstein* and Mary T. Fairhurst Contribution from the Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada. Received August 6, I974 Abstract: The binding of methylmercury, CH3HgIi, by the amino acids cysteine and penicillamine and by the tripeptide glutathione has been investigated by proton and carbon-1 3 magnetic resonance spectroscopy. Of the binding sites in these molecules, methylmercury binds most strongly to the ionized sulfhydryl group, with no detectable dissociation of a one-to-one methylmercury-sulfhydryl complex over the p H range 0- 14. Evidence is presented for some protonation of the methylmercury-complexed sulfhydryl group of glutathione at pH