title: Separation and identification of selenotrisulfides in epithelial cell homogenates by LC-ICP-MS and LC-ESI-MS after incubation with selenite.
abstract: To elucidate how selenite is metabolised in the intestine after oral intake, it was incubated with homogenized epithelial cells from pigs. When the metabolites were analysed by LC-ICP-MS, two major selenium metabolites were separated in the supernatant from the homogenate. These metabolites were formed instantly but disappeared within 15 min. No other selenium-containing compounds appeared during this time. Hence, the secondary reaction products were either volatilised or precipitated. To verify the identity of the compounds, a larger amount of selenite was incubated with epithelial cells. The presence of Cys-Se-SG and GS-Se-SG was verified by LC-ESI-MS. Selenotrisulfides were synthesized by reaction of L-cysteine and L-glutathione with sodium selenite. The reaction mixture contained three main products: selenodicysteine (Cys-Se-Cys), selenocysteine glutathione (Cys-Se-SG), and selenodiglutathione (GS-Se-SG). The two transient selenium compounds in the epithelial cell incubation mixture co-eluted with the synthesized Cys-Se-SG and GS-Se-SG, respectively. The identities of these compounds were verified by LC-ESI-MS. Hence, these selenium metabolites have now been identified by ESI-MS after isolation from epithelial cells.
authors.affiliation: Department of Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100, Copenhagen, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Gabel-Jensen
authors.forename: Bente
authors.initials: B
authors.lastname: Gammelgaard
authors.forename: Lars
authors.initials: L
authors.lastname: Bendahl
authors.forename: Stefan
authors.initials: S
authors.lastname: Stürup
authors.forename: Ole
authors.initials: O
authors.lastname: Jøns
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D004847:Epithelial Cells / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D018036:Selenium Compounds / Q000032:analysis*; D012680:Sensitivity and Specificity; D018038:Sodium Selenite / Q000737:chemistry*; D013440:Sulfides / Q000032:analysis*; D013552:Swine
chemical_list: D018036:Selenium Compounds; D013440:Sulfides; C059755:selenotrisulfide; D018038:Sodium Selenite