Protein disulfide isomerase, or PDI, is an enzyme in the endoplasmic reticulum (ER) in eukaryotes and the periplasm of bacteria that catalyzes the formation and breakage of disulfide bonds between cysteine residues within proteins as they fold. This allows proteins to quickly find the correct arrangement of disulfide bonds in their fully folded state, and therefore the enzyme acts to catalyze protein folding.
Thioredoxin reductases are enzymes that reduce thioredoxin (Trx). Two classes of thioredoxin reductase have been identified: one class in bacteria and some eukaryotes and one in animals. In bacteria TrxR also catalyzes the reduction of glutaredoxin like proteins known as NrdH. Both classes are flavoproteins which function as homodimers. Each monomer contains a FAD prosthetic group, a NADPH binding domain, and an active site containing a redox-active disulfide bond.
Thioredoxin is a class of small redox proteins known to be present in all organisms. It plays a role in many important biological processes, including redox signaling. In humans, thioredoxins are encoded by TXN and TXN2 genes. Loss-of-function mutation of either of the two human thioredoxin genes is lethal at the four-cell stage of the developing embryo. Although not entirely understood, thioredoxin is linked to medicine through their response to reactive oxygen species (ROS). In plants, thioredoxins regulate a spectrum of critical functions, ranging from photosynthesis to growth, flowering and the development and germination of seeds. Thioredoxins play a role in cell-to-cell communication.
Ribonucleoside-triphosphate reductase (EC 1.17.4.2, ribonucleotide reductase, 2'-deoxyribonucleoside-triphosphate:oxidized-thioredoxin 2'-oxidoreductase) is an enzyme with systematic name 2'-deoxyribonucleoside-triphosphate:thioredoxin-disulfide 2'-oxidoreductase. This enzyme catalyses the following chemical reaction
Glutaredoxins are small redox enzymes of approximately one hundred amino-acid residues that use glutathione as a cofactor. In humans this oxidation repair enzyme is also known to participate in many cellular functions, including redox signaling and regulation of glucose metabolism. Glutaredoxins are oxidized by substrates, and reduced non-enzymatically by glutathione. In contrast to thioredoxins, which are reduced by thioredoxin reductase, no oxidoreductase exists that specifically reduces glutaredoxins. Instead, glutaredoxins are reduced by the oxidation of glutathione. Reduced glutathione is then regenerated by glutathione reductase. Together these components compose the glutathione system.
Betaine reductase is an enzyme that catalyzes the chemical reaction
In enzymology, a glycine reductase (EC 1.21.4.2) is an enzyme that catalyzes the chemical reaction
Arsenate reductase (glutaredoxin) (EC 1.20.4.1) is an enzyme that catalyzes the chemical reaction
Adenylyl-sulfate reductase (thioredoxin) is an enzyme that catalyzes the chemical reaction
In enzymology, a L-methionine (S)-S-oxide reductase (EC 1.8.4.13) is an enzyme that catalyzes the chemical reaction
In enzymology, a peptide-methionine (R)-S-oxide reductase (EC 1.8.4.12) is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoadenylyl-sulfate reductase (thioredoxin) is an enzyme that catalyzes the chemical reaction
In enzymology, a trimethylamine-N-oxide reductase (cytochrome c) (EC 1.7.2.3) is an enzyme that catalyzes the chemical reaction
Peptide methionine sulfoxide reductase (Msr) is a family of enzymes that in humans is encoded by the MSRA gene.
Ferredoxin-thioredoxin reductase EC 1.8.7.2, systematic name ferredoxin:thioredoxin disulfide oxidoreductase, is a [4Fe-4S] protein that plays an important role in the ferredoxin/thioredoxin regulatory chain. It catalyzes the following reaction:
Methionine sulfoxide is the organic compound with the formula CH3S(O)CH2CH2CH(NH2)CO2H. It is an amino acid that occurs naturally although it is formed post-translationally.
Methionine-S-oxide reductase (EC 1.8.4.5, methyl sulfoxide reductase I and II, acetylmethionine sulfoxide reductase, methionine sulfoxide reductase, L-methionine:oxidized-thioredoxin S-oxidoreductase) is an enzyme with systematic name L-methionine:thioredoxin-disulfide S-oxidoreductase. This enzyme catalyses the following chemical reaction
L-methionine:oxidized-thioredoxin S-oxidoreductase may refer to:
Peptide-methionine (S)-S-oxide reductase (EC 1.8.4.11, MsrA, methionine sulphoxide reductase A, methionine S-oxide reductase (S-form oxidizing), methionine sulfoxide reductase A, peptide methionine sulfoxide reductase, formerly protein-methionine-S-oxide reductase) is an enzyme with systematic name peptide-L-methionine:thioredoxin-disulfide S-oxidoreductase (L-methionine (S)-S-oxide-forming). This enzyme catalyses the following chemical reaction
Oxidation response is stimulated by a disturbance in the balance between the production of reactive oxygen species and antioxidant responses, known as oxidative stress. Active species of oxygen naturally occur in aerobic cells and have both intracellular and extracellular sources. These species, if not controlled, damage all components of the cell, including proteins, lipids and DNA. Hence cells need to maintain a strong defense against the damage. The following table gives an idea of the antioxidant defense system in bacterial system.
