Determination of Proteinaceous Selenocysteine in Selenized Yeast

Katarzyna Bierla (1) , Ryszard Lobinski (1) , Joanna Szpunar (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

A method for the quantitation of proteinaceous selenocysteine (SeCys) in Se-rich yeast was developed. The method is based on the reduction of the Se-Se and S-Se bridges with dithiotretiol, derivatization with iodoacetamide (carbamidomethylation), followed by HPLC-ICP MS. The chromatographic conditions were optimized for the total recovery of the proteinaceous selenocysteine, the minimum number of peaks in the chromatogram (reduction of derivatization products of other Se-species present) and the baseline separation. A typical chromatogram of a proteolytic digest of selenized yeast protein consisted of up to five peaks (including SeMet, carbamidomethylated (CAM)-SeCys, and Se(CAM) 2) identified by retention time matching with available standards and electrospray MS. Inorganic selenium non-specifically attached to proteins and selenomethionine could be quantified (in the form of Se(CAM) 2) along with SeCys. Selenocysteine, selenomethionine, inorganic selenium, and the water soluble-metabolite fraction accounted for the totality of selenium species in Se-rich yeast.

Mots clés: selenized yeast; selenocysteine; HPLC-ICP MS; HPLC-ESI MS

Domaines: Chimie

Katarzyna Bierla, Ryszard Lobinski, Joanna Szpunar. Determination of Proteinaceous Selenocysteine in Selenized Yeast. International Journal of Molecular Sciences, 2018, 19 (2), pp.543. ⟨10.3390/ijms19020543⟩. ⟨hal-03133487⟩