Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:1.11.1.9 (
glutathione peroxidase
)
22,002
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Selenium has a highly specific metabolism centered around its incorporation as selenocysteine into selenoproteins. An outline of this metabolism has emerged from recent molecular biological and biochemical studies of bacteria and animals. A unique tRNA, designated tRNA[Ser]Sec, is charged with L-serine, which is then converted through at least two steps to selenocysteine. With the aid of a unique translation factor, the selenocysteinyl-tRNA[Ser]Sec recognizes specific UGA codons in mRNA to insert selenocysteine into the primary structure of selenoproteins. Turnover of selenoproteins presumably liberates selenocysteine which is toxic in its free form.
Selenocysteine beta-lyase
catabolizes free selenocysteine and makes its selenium available for reuse. Proteins contain almost all the selenium in animals. Of the known selenoproteins, the glutathione peroxidases contain the most selenium. Cellular and plasma glutathione peroxidases are products of different genes but have 44% identity of amino acid sequence. There is evidence for other proteins of this family. Selenoprotein P is an unrelated protein with multiple selenocysteines in its primary structure. It contains most of the selenium in rat plasma. Studies of the regulation of cellular glutathione peroxidase by selenium have yielded conflicting results, but there is a strong suggestion that mRNA levels of the rodent liver
glutathione peroxidase
decrease in selenium deficiency. This could be a mechanism for directing selenium to the synthesis of other selenoproteins. Although present knowledge allows construction of an outline of selenium metabolism, several steps have not been characterized and little is known about mechanisms of its regulation.
...
PMID:Molecular biology of selenium with implications for its metabolism. 183 May 57
Cardiac hypertrophy is defined as the enlargement of the cardiac myocytes, leading to improper nourishment and oxygen supply due to the increased functional demand. This increased stress on the cardiac system commonly leads to myocardial infarction, contributing to 85% of all cardiac-related deaths. Cystathionine gamma-lyase- (CSE-) derived H
2
S is a novel gasotransmitter and plays a critical role in the preservation of cardiac functions.
Selenocysteine lyase
(
SCLY
) has been identified to produce H
2
Se, the selenium homologue of H
2
S. Deficiency of selenium is often found in Keshan disease, a congestive cardiomyopathy. The interaction of H
2
S and H
2
Se in cardiac cell hypertrophy has not been explored. In this study, cell viability was evaluated with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Oxidative stress and cell size were observed through immunostaining. The expression of genes was determined by real-time PCR and western blot. Here, we demonstrated that incubation of rat cardiac cells (H9C2) with H
2
O
2
lead to increased oxidative stress and cell surface area, which were significantly attenuated by pretreatment of either H
2
S or H
2
Se. H
2
S incubation induced
SCLY
/H
2
Se signaling, which next caused higher expressions and activities of selenoproteins, including
glutathione peroxidase
and thioredoxin reductase. Furthermore, deficiency of CSE inhibited the expressions of
SCLY
and selenoprotein P in mouse heart tissues. We also found that both H
2
S and H
2
Se stimulated Nrf2-targeted downstream genes. These data suggests that H
2
S protects against cardiac hypertrophy through enhancement of a group of antioxidant proteins.
...
PMID:H
2
S Protects against Cardiac Cell Hypertrophy through Regulation of Selenoproteins. 3158 42
