title: Characterization and quantification of metallothionein isoforms by capillary electrophoresis-inductively coupled plasma-isotope-dilution mass spectrometry.
abstract: In a new approach to the characterization and quantification of metallothionein isoforms an on-line isotope-dilution method in combination with the coupling of capillary electrophoresis (CE) to an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS) is reported. Metallothionein (MT) isoforms are separated by CE and the elements Cu, Zn, Cd, and S are detected simultaneously by use of ICP-SFMS in the medium resolution mode. On-line isotope dilution is performed by continuous introduction of an isotopically enriched, species-unspecific spike solution after the separation step. MT from rabbit liver and a further purified MT-1 isoform were quantified by determination of sulfur, and the stoichiometric compositions of the metalloprotein complexes are characterized by determination of their sulfur-to-metal ratios.
authors.affiliation: GKSS Research Center, Geesthacht, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schaumlöffel
authors.forename: Andreas
authors.initials: A
authors.lastname: Prange
authors.forename: Gizelher
authors.initials: G
authors.lastname: Marx
authors.forename: Klaus G
authors.initials: KG
authors.lastname: Heumann
authors.forename: Peter
authors.initials: P
authors.lastname: Brätter
mesh_terms: D000465:Algorithms; D002104:Cadmium / Q000032:analysis; D003300:Copper / Q000032:analysis; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D007553:Isotope Labeling / Q000295:instrumentation / Q000379:methods; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D008668:Metallothionein / Q000032:analysis*; D020033:Protein Isoforms / Q000032:analysis; D013455:Sulfur / Q000032:analysis; D013997:Time Factors; D015032:Zinc / Q000032:analysis
chemical_list: D020033:Protein Isoforms; D002104:Cadmium; D013455:Sulfur; D003300:Copper; D008668:Metallothionein; D015032:Zinc