title: Multimodal analysis of metals in copper-zinc superoxide dismutase isoforms separated on electrophoresis gels.
abstract: It has been suggested that copper-zinc superoxide dismutase (CuZnSOD) isoforms of distinct isoelectric point (pI) could result from differences in their metallation state. Our aim was then to develop and validate analytical methods for the determination and understanding of metallation states in human CuZnSOD isoforms. To avoid metal losses during sample preparation steps, CuZnSOD isoforms were separated according to their pI using non-denaturing isoelectric focusing (IEF) gel electrophoresis. Metal quantification was directly performed in-gel. Cu/Zn ratios of CuZnSOD isoforms were quantified by Particle-Induced X-ray Emission (PIXE) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Cu/Zn ratios were measured close to the value of 1 as expected from the known stoichiometry of CuZnSOD with slight, but statistically significant, differences between acidic and basic isoforms. Overall, this study demonstrates that metal quantification can be performed directly on metalloproteins separated on electrophoresis gels.
authors.affiliation: Groupe d'Imagerie Chimique Cellulaire et Spéciation, Laboratoire de Chimie Nucléaire Analytique et Bioenvironnementale (CNAB), CNRS UMR5084, Université de Bordeaux 1, chemin du Solarium, 33175 Gradignan Cedex, France.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Chevreux
authors.forename: Stéphane
authors.initials: S
authors.lastname: Roudeau
authors.forename: Aurélien
authors.initials: A
authors.lastname: Fraysse
authors.forename: Asunción
authors.initials: A
authors.lastname: Carmona
authors.forename: Guillaume
authors.initials: G
authors.lastname: Devès
authors.forename: Pier Lorenzo
authors.initials: PL
authors.lastname: Solari
authors.forename: Sandra
authors.initials: S
authors.lastname: Mounicou
authors.forename: Ryszard
authors.initials: R
authors.lastname: Lobinski
authors.forename: Richard
authors.initials: R
authors.lastname: Ortega
mesh_terms: D004586:Electrophoresis / Q000379:methods*; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000302:isolation & purification*; D013058:Mass Spectrometry; D013482:Superoxide Dismutase / Q000302:isolation & purification*
chemical_list: D007527:Isoenzymes; D013482:Superoxide Dismutase