Aspects of Mercury(II) Thiolate Chemistry and the Biological Behavior of Mercury Compounds

Complex formation between mercury compounds and thiols, e.g. cysteine, is believed to play a major role in the biological chemistry of mercury. The greater affinity of Hg(II) and MeHg(II) for thiols than other possible biological donor ligands has been well documented by stability constant studies in aqueous solution. Our interest in mercury(II) thiolates stems from studies of the chemistry of the antidote British anti-Lewisite which indicated that the structure and reactivity of simple thiolate complexes was little understood. In this review our recent work on the interaction of inorganic and organomercury compounds with British anti-Lewisite, simple thiols and sulphur containing amino acids is discussed, followed by an account of animal studies of the distribution and metabolism of phenylmercury compounds. In discussing the implications of chemical results, e.g. reactivity of thiolates, for the biological behaviour of mercury compounds it is assumed here that chemical studies provide only plausible pathways for biological behaviour.