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Updated: May 8, 2026
12:59
A Study of the Complexation of Mercury(II) with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry
Published on: January 8, 2016
Mercury(II) complex formation with N-acetylcysteine.
Farideh Jalilehvand1, Karnjit Parmar, Stephen Zielke
1Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada. faridehj@ucalgary.ca.
Metallomics : Integrated Biometal Science
|August 30, 2013
Summary
N-Acetylcysteine (H2NAC) forms complexes with mercury (Hg(II)) at physiological and alkaline pH. A novel tetra-thiolate Hg(NAC)4(6-) species dominates in ligand excess at alkaline pH.
Area of Science:
- Biochemistry
- Inorganic Chemistry
- Structural Biology
Background:
- N-Acetylcysteine (H2NAC) is an antioxidant and potential antidote for metal toxicity.
- Limited structural data exists for mercury (Hg(II)) complexes with N-acetylcysteine, despite known binding affinities.
Purpose of the Study:
- To investigate the structural nature of Hg(II)-N-acetylcysteine complexes in aqueous solution.
- To elucidate the influence of N-acetylcysteine's blocked amino group on Hg(II) complexation.
Main Methods:
- Hg L3-edge EXAFS spectroscopy
- (199)Hg NMR spectroscopy
- Raman spectroscopy
- Aqueous solutions at pH 7.5 and 10.5 with high concentrations of Hg(II) and N-acetylcysteine.
Main Results:
- At physiological pH, Hg(NAC)2(2-) and Hg(NAC)3(4-) complexes were identified.
- A novel tetra-thiolate species, Hg(NAC)4(6-), was found to dominate in ligand excess at alkaline pH.
- Comparison with cysteine and penicillamine highlighted the role of the blocked amino group in N-acetylcysteine.
Conclusions:
- The study reveals the speciation and structural characteristics of Hg(II)-N-acetylcysteine complexes.
- N-Acetylcysteine forms distinct complexes with Hg(II) depending on pH and ligand concentration.
- The blocked amino group of N-acetylcysteine influences its coordination behavior with Hg(II).
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