title: Structural characterization of Cd²⁺ complexes in solution with DMSA and DMPS.
abstract: Meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercaptopropane-1-sulfonic acid (DMPS) are chelating agents which have been used clinically to treat patients suffering from Pb(2+) or Hg(2+) exposure. Cd(2+) is a related environmental pollutant that is of increasing public health concern due to a demonstrated dose-response between urinary Cd level and an increased risk of diabetes. However, therapeutically effective chelating agents which enhance the excretion of Cd(2+) from humans have yet to be identified. Here we present a structural characterization of complexes of DMSA and DMPS with Cd(2+) at physiological pH using a combination of X-ray absorption spectroscopy, size exclusion chromatography and density functional theory. The results indicate a complex chemistry in which multi-metallic forms are important, but are consistent with both DMPS and DMSA acting as true chelators, using two thiolates for DMPS and one thiolate and one carboxylate for DMSA.
authors.affiliation: Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Elham
authors.initials: E
authors.lastname: Zeini Jahromi
authors.affiliation: Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada. Electronic address: jgailer@ucalgary.ca.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gailer
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
authors.forename: Ingrid J
authors.initials: IJ
authors.lastname: Pickering
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada. Electronic address: g.george@usask.ca.
authors.forename: Graham N
authors.initials: GN
authors.lastname: George
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry* / Q000302:isolation & purification; D002614:Chelating Agents; D002850:Chromatography, Gel; D056831:Coordination Complexes / Q000737:chemistry / Q000302:isolation & purification; D008958:Models, Molecular; D008968:Molecular Conformation; D012996:Solutions; D013054:Spectrophotometry, Atomic; D004113:Succimer / Q000737:chemistry*; D014494:Unithiol / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D019187:Cadmium Compounds; D002614:Chelating Agents; D056831:Coordination Complexes; D012996:Solutions; D014494:Unithiol; D004113:Succimer
keywords: Cadmium; Chelation therapy agents; X-ray absorption spectroscopy