Disease relevance of C05704

• The subacute oral toxicity of selenocystine and chemical form of selenium in the liver following exposure to this compound were assessed in ICR male mice [1].
• The effects of low concentrations (1.0 mmol/l of selenite and seleno-dl-cystine were tested alone, or in combination with NaF, on growth, glycolysis, and survival of Streptococcus mutans GS-5 [2].
• Experiments were conducted to determine the relative effectiveness of selenium (Se) from sodium selenite, selenomethionine and selenocystine for promoting weight gain and preventing exudative diathesis [3].
• The transport systems for selenomethionine/methionine and selenocystine/cystine in Escherichia coli K-12 appear to be cooperative [4].

High impact information on C05704

• Purified rat liver thioredoxin reductase catalyzed the disappearance of NADPH in the presence of low micromolar concentrations of the ascorbyl free radical that were generated from ascorbate by ascorbate oxidase, and this effect was markedly stimulated by selenocystine [5].
• Human thioredoxin reductase directly reduces lipid hydroperoxides by NADPH and selenocystine strongly stimulates the reaction via catalytically generated selenols [6].
• The rate of the reduction of 15-HPETE by the HP-TR/NADPH peroxidase system was increased 8-fold by the presence of 2.5 microM selenocystine, a diselenide amino acid [6].
• Hydrogen peroxide and 15-HPETE were reduced at approximately the same rate by HP-TR, thioredoxin, and selenocystine [6].
• Our data suggest two novel pathways for the reduction and detoxification of lipid hydroperoxides, hydrogen peroxide, and organic hydroperoxides, i.e. the human thioredoxin reductase-dependent pathway and a coupled reduction in the presence of selenols or selenide resulting from the reduction of selenocystine or selenodiglutathione [6].

Chemical compound and disease context of C05704

• Selenite, selenodiglutathione (GS-Se-SG) and selenocystine are efficiently reduced by thioredoxins and also directly by NADPH and mammalian TR but not by the E. coli enzyme [7].

Biological context of C05704

• Competitive binding affinity studies with unlabeled test compounds revealed that selenium dioxide and selenocystine showed high binding affinity (90-95%) for the selenite-binding site on SeBP [8].
• Selenite, selenocystine, and selenodioxide induced apoptosis in HepG2 cells and mediated oxidation of protein thiol groups in both HepG2 cells and isolated mitochondria [9].
• Selenite did not affect protein kinase A, whereas GSSeSG and selenocystine inactivated the catalytic subunit after dissociation from the regulatory subunit at concentrations 100- and 800-fold, respectively, higher than that required for PKC inactivation [10].
• Mechanisms of selenium methylation and toxicity in mice treated with selenocystine [11].
• Interestingly, 0.625 or 1.25 micromol/L copper did not inhibit selenocystine-induced cell cycle arrest [12].

Anatomical context of C05704

• The deposition of selenium (Se) in erythrocyte proteins was studied in rats fed Se as sodium selenite, selenocystine, selenomethionine (Se-Met), high Se wheat or selenium-enriched yeast [13].
• This investigation was carried out to elucidate the chemical form of selenium-containing metabolite in small intestine of ICR male mice orally administered selenocystine (CySeSeCy) [14].
• From an examination of the distribution of the selenocysteine-containing metabolite, it was recognized that this metabolite exists in plasma and liver cytosol of mice after oral administration of selenocystine [15].
• 2. Several analogues, including thiazolylanine, triazolalanine and selenocystine both stimulated protein synthesis and produced labile protein in reticulocytes [16].
• In this study, the triple-lumen perfusion method was used to measure the rate of absorption of trace quantities of selenium (50 micrograms/liter in a physiological electrolyte solution) from the jejunum when given as D,L-selenomethione, D,L-selenocystine, or sodium selenite to healthy dogs in vivo [17].

Associations of C05704 with other chemical compounds

• After selenium supplementation, with either sodium selenite or selenocystine, we observed an increase in growth of P. falciparum only in with sodium selenite, whereas higher GPx activities were noted in parasites grown in media supplemented with both [18].
• Isomorphous replacement of cystine with selenocystine in endothelin: oxidative refolding, biological and conformational properties of [Sec3,Sec11,Nle7]-endothelin-1 [19].
• The selenium K-edge X-ray absorption spectra of selenomethionine, selenocysteine, selenocystine, and sulfo-selenocystine in solution are compared with the corresponding sulfur K-edge spectra of the sulfur analogues of these compounds [20].
• Taken together, these results suggest that the accessible redox-active cysteine residues present in the PKC catalytic domain can react with certain specificity with redox-active selenocompounds such as selenite, selenocystine, and GSSeSG relative to other protein kinases tested [10].
• Generally, CF sera showed lower values of total Se, Selenocystine (SeC), and cationic/neutral Se compounds compared to serum of healthy persons [21].

Gene context of C05704

• Selenocystine is efficiently reduced into two molecules of the selenol amino acid selenocysteine by mammalian TR with a K(m)-value (6 mumol.L-1) and a high turnover number (kappa cat 3200 min-1) almost identical to the natural substrate Trx-S2 [7].
• The enhanced chemiluminescence generated by selenite and selenocystine in the presence of the tumor cells was also suppressed by superoxide dismutase, catalase and glutathione peroxidase [22].
• The two compounds showing significant tumor reduction (OSCA and selenocystine) were the only two compounds that showed ubiquity of changes, elevating both selenium levels and GPx activity in both liver and RBC [23].
• Glutathione peroxidase (GSH-Px) activity in B16 cells was more sensitive than in pB16 cells to the activating effect of selenite, and particularly of seleno-DL-cystine: however, cell-free controls indicated that activation was mainly due to glutathione reductase [24].
• A novel selenocystine-beta-cyclodextrin conjugate that acts as a glutathione peroxidase mimic [25].

Analytical, diagnostic and therapeutic context of C05704

• Diastereoisomers of selenocystine were identified by HPLC in the AccQ-Tag mode [26].
• To elucidate the selenium methylation mechanism, animals received a single oral administration of selenocystine (Se-Cys; 5, 10, 20, 30, 40, or 50 mg/kg) [11].
• Selenium content in the small intestine of animals treated with 50 mg/kg selenocystine significantly increased 15 min, 1 h and 6 h after treatment [15].
• Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis visualized two bands with subunit molecular weights around 15 kDa. o-Phthaldialdehyde precolumn derivatization and reverse-phase high-performance liquid chromatography showed that the protein contains selenocysteine or selenocystine residues [27].

References