Formation of Hg(II) Tetrathiolate Complexes with Cysteine at Neutral pH.

ABSTRACT: Mercury(II) ions precipitate from aqueous cysteine (H₂Cys) solutions containing H₂Cys/Hg(II) mole ratio ≥ 2.0 as Hg(S-HCys)₂. In absence of additional cysteine, the precipitate dissolves at pH ~12 with the [Hg(S,N-Cys)₂]^2- complex dominating. With excess cysteine (H₂Cys/Hg(II) mole ratio ≥ 4.0), higher complexes form and the precipitate dissolves at lower pH values. Previously, we found that tetrathiolate [Hg(S-Cys)₄]^6- complexes form at pH = 11.0; in this work we extend the investigation to pH values of physiological interest. We examined two series of Hg(II)-cysteine solutions in which C_Hg(II) varied between 8 - 9 mM and 80 - 100 mM, respectively, with H₂

SUBMITTER: Warner T 

PROVIDER: S-EPMC4824553 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature