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Literature summary for 1.8.1.9 extracted from

  • Zhong, L.; Holmgren, A.
    Essential role of selenium in the catalytic activities of mammalian thioredoxin reductase revealed by characterization of recombinant enzymes with selenocysteine mutations (2000), J. Biol. Chem., 275, 18121-18128.
    View publication on PubMed
Search for more literature for 1.8.1.9

Activating Compound

Activating Compound Comment Organism Structure
cysteine part of the active site Rattus norvegicus

Cloned(Commentary)

Cloned (Comment) Organism
overexpression of antisense mutant in Escherichia coli, expression of wild-type in COS-7 cells, amino acid sequence analysis Rattus norvegicus

Protein Variants

Protein Variants Comment Organism
additional information truncated enzyme mutant without catalytic active C-terminus Rattus norvegicus
SeC498C antisense technique, exchange in the catalytic active selenosulfide at the C-terminus, resulting in higher pH-optimum, 100fold lower turnover number, 10fold lower Km-value, no activity with H2O2 Rattus norvegicus
SeC498G antisense technique, reduced activity Rattus norvegicus
SeC498S antisense technique, reduced activity Rattus norvegicus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0004
-
 thioredoxin SeC498C mutant, human thioredoxin Rattus norvegicus
0.0033
-
 human thioredoxin wild-type enzyme Rattus norvegicus
2.5
-
 H2O2 wild-type enzyme, Km-value can be reduced by addition of selenocysteine Rattus norvegicus

Metals/Ions

Metals/Ions Comment Organism Structure
selenocysteine contains selenocysteine as part of the redox active selenosulfide in the active center Rattus norvegicus
selenocysteine encoded by TGA stop codon Rattus norvegicus

Organism

Organism UniProt Comment Textmining
Rattus norvegicus
-
-
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
-
 several mutants with different substrates Rattus norvegicus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
5,5'-dithiobis(2-nitrobenzoic acid) + NADPH i.e. DTNB Rattus norvegicus 2-nitro-5-thiobenzoate + NADP+
-
 ?
5,5'-dithiobis(2-nitrobenzoic acid) + NADPH coupled assay Rattus norvegicus 2-nitro-5-thiobenzoate + NADP+
-
 ?
human thioredoxin + NADP+
-
 Rattus norvegicus human thioredoxin disulfide + NADPH + H+
-
 r
methylseleninate + H2O2 addition of selenocysteine increases the activity by 20% Rattus norvegicus ?
-
 ?
methylseleninate + H2O2 only wild-type enzyme Rattus norvegicus ?
-
 ?
thioredoxin + NADP+ coupled assay with DTNB Rattus norvegicus thioredoxin disulfide + NADPH
-
 ?
thioredoxin + NADP+ coupled assay, measurement of NADPH oxidation in presence of insulin and thioredoxin Rattus norvegicus thioredoxin disulfide + NADPH
-
 ?
thioredoxin + NADP+ in presence of NADPH, coupled assay Rattus norvegicus thioredoxin disulfide + NADPH + H+
-
 ?

Synonyms

Synonyms Comment Organism
TrxR
-
 Rattus norvegicus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.243
-
 thioredoxin SeC498C mutant enzyme, human thioredoxin Rattus norvegicus
41.7
-
 thioredoxin wild-type enzyme, human thioredoxin Rattus norvegicus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
 wild-type enzyme Rattus norvegicus
9
-
 SeC498C mutant enzyme, broad optimum Rattus norvegicus

pH Range

pH Minimum pH Maximum Comment Organism
4.2 10.5 wild-type and mutant Rattus norvegicus

Cofactor

Cofactor Comment Organism Structure
FAD
-
 Rattus norvegicus
NADPH
-
 Rattus norvegicus