Thioredoxin (ADF) Recombinant Protein

Thioredoxin is a 12-kD oxidoreductase enzyme containing a dithiol-disulfide active site. It is ubiquitous and found in many organisms from plants and bacteria to mammals. Multiple in vitro substrates for thioredoxin have been identified, including ribonuclease, choriogonadotropins, coagulation factors, glucocorticoid receptor, and insulin. Reduction of insulin is classically used as an activity test.[supplied by OMIM]

Function: Participates in various redox reactions through the reversible oxidation of its active center dithiol to a disulfide and catalyzes dithiol-disulfide exchange reactions. Plays a role in the reversible S-nitrosylation of cysteine residues in target proteins, and thereby contributes to the response to intracellular nitric oxide. Nitrosylates the active site Cys of CASP3 in response to nitric oxide (NO), and thereby inhibits caspase-3 activity. Induces the FOS/JUN AP-1 DNA-binding activity in ionizing radiation (IR) cells through its oxidation/reduction status and stimulates AP-1 transcriptional activity. Ref.16 Ref.18 Ref.19 Ref.21 Ref.24ADF augments the expression of the interleukin-2 receptor TAC (IL2R/P55). Ref.16 Ref.18 Ref.19 Ref.21 Ref.24

Subunit structure: Homodimer; disulfide-linked. Interacts with TXNIP through the redox-active site. Interacts with MAP3K5 and CASP3. In case of infection, interacts with S.typhimurium protein slrP. Interacts with APEX1; the interaction stimulates the FOS/JUN AP-1 DNA-binding activity in a redox-dependent manner. Ref.18 Ref.20 Ref.26 Ref.35 Ref.36

Subcellular location: Nucleus. Cytoplasm. Secreted. Note: Secreted by a leaderless secretory pathway. Predominantly in the cytoplasm in non irradiated cells. Radiation induces translocation of TRX from the cytoplasm to the nucleus. Ref.17 Ref.18 Ref.19

Induction: Up-regulated by ionizing radiation. Ref.19

Post-translational modification: In the fully reduced protein, both Cys-69 and Cys-73 are nitrosylated in response to nitric oxide (NO). When two disulfide bonds are present in the protein, only Cys-73 is nitrosylated. Cys-73 can serve as donor for nitrosylation of target proteins.In case of infection, ubiquitinated by S.typhimurium protein slrP, leading to its degradation.

Sequence similarities: Belongs to the thioredoxin family.Contains 1 thioredoxin domain.