Mercury complexes thiols

The thiol group of Cys is the most reactive side residue. The thiolate anion is a potent nucleophile and the thiol is a week acid with pKj = 8.37. Cys serves as the active site residues of many oxidoreductases. Cys residues form complexes of varying stability with a variety of metal ions. It reacts with organic mercurials stoichiometiically. Thiol residues of Cys cross link to form disulfide bonds (cystine) in proteins. Thiols and disulfides undergo rapid exchange and redox reactions. 

Aaseth, J, and Friedheim, E.A.H. (1978). Treatment of methyl-mercury poisoning in mice with 2,3-dimercaptosuccinic acid and other complexing thiols. Acta Pharmacol. Toxicol.. 42. 248-252. 

In an earlier paper Westoo pointed out that if methylmercury attached itself to a sulphur atom by reaction with a thiol or hydrogen sulphide then the non-volatile HgS compound produced would not be included in the determination. More recently he has developed a modification to this method described below, to render it applicable to a wider range of foodstuffs (egg-yolk and white, meat and liver) by binding interfering thiols in the benzene extract of the sample to mercuric ions added in excess or, by extracting the benzene extract with aqueous cysteine to form the cysteine-methyl mercury complex. 

Antibacterial complexes such as silver sulfadiazene and some mercurials also manifest antiviral activity [51, 52]. Mersalyl, a diuretic (Chapter 12), has some in vivo action when mice treated with lethal doses of coxsackie virus are then administered the mercury complex [53]. The levels needed for 100% inactivation in vitro by mercurials is dependent on the virus, and thiols reverse the antiviral effect [54]. Conformational changes and breakdown into subunits have also been observed after mercury treatment [51],... 

Some analogous in vitro reactions of methylcobalt complexes are known, e.g., the methylation of thiols (see Section VI,C,3) and of mercury(II)... 

Thiols are easily oxidized to disulfides in solution, but this reaction occurs only very slowly at most electrode surfaces. However, use can be made of the unique reaction between thiols and mercury to detect these compounds at very favorable potentials. The thiol and mercury form a stable complex which is easily oxidized, in a formal sense it is mercury and not the thiol which is actually oxidized in these reactions. For the LCEC determination of thiols a Au/Hg amalgam electrode is used Using a series dual-electrode both thiols and disulfides can be determined in a single chromatographic experiment... 

The oxidation of thiols on mercury and some other metals (M = Zn, Cd) can be used for the preparation of different bis-thiolate complexes M(SR2) [18]. 

Chalcogenolato complexes of mercury can be prepared by a variety of methods. Early preparations involve the reactions of thiols with mercury cyanide,1 the reaction of mercury salts with alkali chalcogenolates, electrochemical methods,2 and the oxidative addition of dichalcogenides to metallic mercury.3 The last method is very convenient for the preparation of complexes with sterically undemanding ligands, but becomes less facile as the... 

The kinetics of reaction of a number of A-nitrosothiols (334) in water with mercury(II) salts have been reported. Reaction is first order in both reactants and the products are nitrous acid and the corresponding thiol-Hg2+ complex. The mechanism involves slow attack by water at the nitrogen atom in the complex.300 The same group has also studied the copper(II)-catalysed decomposition of the, -nitrosothiols derived from penicillamine, cysteamine, thiomalic acid, A -acetylpenicillaminc, and cysteine.301... 

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