TY - JOUR

T1 - Separation and identification of selenotrisulfides in epithelial cell homogenates by LC-ICP-MS and LC-ESI-MS after incubation with selenite

AU - Gabel-Jensen, Charlotte

AU - Gammelgaard, Bente

AU - Bendahl, Lars

AU - Stürup, Stefan

AU - Jøns, Ole

PY - 2006

Y1 - 2006

N2 - 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.

AB - 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.

KW - Animals

KW - Chromatography, Liquid

KW - Epithelial Cells

KW - Mass Spectrometry

KW - Selenium Compounds

KW - Sensitivity and Specificity

KW - Sodium Selenite

KW - Sulfides

KW - Swine

U2 - 10.1007/s00216-005-0178-3

DO - 10.1007/s00216-005-0178-3

M3 - Journal article

C2 - 16328239

VL - 384

SP - 697

EP - 702

JO - Analytical and Bioanalytical Chemistry

JF - Analytical and Bioanalytical Chemistry

SN - 1618-2642

IS - 3

ER -