Human GPX3 (Glutathione peroxidase 3) ELISA Kit

Background: Interactions between genetic variants and risk factors in myelodysplastic syndromes are poorly understood. In this case-control study, we analyzed 1 421 single nucleotide polymorphisms in 408 genes involved in cancer-related pathways in 198 patients and 292 controls. Methods: The Illumina SNP Cancer Panel was used for genotyping of samples. The chi-squared, p-values, odds ratios and upper and lower limits of the 95% confidence interval were calculated for all the SNPs that passed the quality control filtering. Results: Gene-based analysis showed nine candidate single nucleotide polymorphisms significantly associated with the disease susceptibility (q-value < 0.05). Four of these polymorphisms were located in oxidative damage/DNA repair genes (LIG1, RAD52, MSH3 and GPX3), which may play important roles in the pathobiology of myelodysplastic syndromes. Two of nine candidate polymorphisms were located in transmembrane transporters (ABCB1 and SLC4A2), contributing to individual variability in drug responses and patient prognoses. Moreover, the variations in the ROS1 and STK6 genes were associated with the overall survival of patients. Conclusions: Our association study identified genetic variants in Czech population that may serve as potential markers for myelodysplastic syndromes.

In this work, we present the first methodical approach to the preparation, molecular characterization and use of a novel type of full-length selenoprotein standard as exemplified for the human plasma selenoproteins, glutathione peroxidase 3 (GPx3) and selenoprotein P (SEPP1), both in non-labeled and stable isotope-labeled forms. Their production was achieved by a cell-free protein synthesis in E. coli extracts. Plasmids with modified coding sequences for GPx3 and SEPP1 were used as DNA templates. In the plasmids, all selenocysteine coding nucleotide triplets (TGA), which in standard conditions serve as stop codons, were site-mutated to cysteine codons (TGT) resulting in exchange of all selenocysteine residues for cysteine residues in the protein amino acid sequence. We named this type of recombinant selenoprotein analog as [Sec-to-Cys] selenoprotein standard. To allow their accurate quantification by inductively coupled plasma mass spectrometry (ICP MS), selenium is introduced into [Sec-to-Cys] selenoprotein standards by replacing Met by SeMet during cell-free protein synthesis. The introduction of e.g. (76)SeMet allows the quantification of [Sec-to-Cys] selenoprotein standards by isotope dilution inductively coupled plasma mass spectrometry (ID ICPMS). Molecular characterization of [Sec-to-Cys] selenoprotein standards is achieved by electrospray tandem mass spectrometry (ESI MS/MS) analysis including a trypsin digestion step. A [Sec-to-Cys]SEPP1 standard containing Se-76-enriched SeMet was successfully applied as a pseudo-species-specific SEPP1 spike for the quantification of natural SEPP1 in human serum/plasma reference materials (BCR-637 and SRM 1950) by species-specific isotope dilution ICP MS using double affinity high performance liquid chromatography separation. [Sec-to-Cys] selenoprotein standards will help to establish novel, validated and traceable analytical methods for the quantification of human plasma selenoproteins.