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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
8
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pubmed:dateCreated |
1999-3-18
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pubmed:databankReference | |
pubmed:abstractText |
A thioredoxin reductase (TrxR), named here TrxR2, that did not react with antibodies to the previously identified TrxR (now named TrxR1) was purified from rat liver. Like TrxR1, TrxR2 was a dimeric enzyme containing selenocysteine (Secys) as the COOH-terminal penultimate residue. A cDNA encoding TrxR2 was cloned from rat liver; the open reading frame predicts a polypeptide of 526 amino acids with a COOH-terminal Gly-Cys-Secys-Gly motif provided that an in-frame TGA codon encodes Secys. The 3'-untranslated region of the cDNA contains a canonical Secys insertion sequence element. The deduced amino acid sequence of TrxR2 shows 54% identity to that of TrxR1 and contained 36 additional residues upstream of the experimentally determined NH2-terminal sequence. The sequence of this 36-residue region is typical of that of a mitochondrial leader peptide. Immunoblot analysis confirmed that TrxR2 is localized almost exclusively in mitochondria, whereas TrxR1 is a cytosolic protein. Unlike TrxR1, which was expressed at a level of 0.6 to 1.6 microgram/milligram of total soluble protein in all rat tissues examined, TrxR2 was relatively abundant (0.3 to 0.6 microgram/mg) only in liver, kidney, adrenal gland, and heart. The specific localization of TrxR2 in mitochondria, together with the previous identification of mitochondria-specific thioredoxin and thioredoxin-dependent peroxidase, suggest that these three proteins provide a primary line of defense against H2O2 produced by the mitochondrial respiratory chain.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
19
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pubmed:volume |
274
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
4722-34
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pubmed:dateRevised |
2007-11-15
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pubmed:meshHeading |
pubmed-meshheading:9988709-Amino Acid Sequence,
pubmed-meshheading:9988709-Animals,
pubmed-meshheading:9988709-Base Sequence,
pubmed-meshheading:9988709-Catalysis,
pubmed-meshheading:9988709-Cloning, Molecular,
pubmed-meshheading:9988709-DNA, Complementary,
pubmed-meshheading:9988709-DNA Transposable Elements,
pubmed-meshheading:9988709-Mitochondria, Liver,
pubmed-meshheading:9988709-Molecular Sequence Data,
pubmed-meshheading:9988709-Rats,
pubmed-meshheading:9988709-Sequence Homology, Amino Acid,
pubmed-meshheading:9988709-Sequence Homology, Nucleic Acid,
pubmed-meshheading:9988709-Subcellular Fractions,
pubmed-meshheading:9988709-Thioredoxin-Disulfide Reductase
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pubmed:year |
1999
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pubmed:articleTitle |
Molecular cloning and characterization of a mitochondrial selenocysteine-containing thioredoxin reductase from rat liver.
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pubmed:affiliation |
Laboratory of Cell Signaling, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA.
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pubmed:publicationType |
Journal Article
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