Protein disulfide isomerases
| Protein disulfide isomerases | ||
|---|---|---|
|
||
| Protein disulfide isomerase | ||
| Mass / length primary structure | 56 kDa, 508 amino acids | |
| Identifier | ||
| Gene name (s) | P4HB; PDI; PDIA1 | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 5.3.4.1 , isomerase | |
Protein disulfide isomerases (also PDI) are enzymes from the class of isomerases that carry out a redox reaction . They serve as protein folding aids , which catalyze the change of disulfide bridges in proteins .
Protein folding
Cysteine can form disulfide bridges via its free thiol group . If there are several cysteine residues in a protein, disulfide bridges can form between the wrong cysteine groups, causing the protein to misfold. In this case, the cell can not use the protein and it is broken down. To avoid this, the disulfide isomerase can break a false bond and introduce a new one. This function is called the thiol-disulfide exchange reaction. It has thioredoxin- like activity.
Structure and localization
PDI is located in eukaryotes in the endoplasmic reticulum (ER) and in prokaryotes in the periplasm . It reaches the ER through a signal peptide , which is split off after transport. PDI is a dimer that itself has cysteine residues in its active center , which participate in the rearrangement of the disulfide bridges.
Individual evidence
- ↑ a b Protein folding - Chemgapedia. Retrieved February 28, 2020 .
- ↑ J. Lundström, A. Holmgren: Protein disulfide-isomerase is a substrate for thioredoxin reductase and has thioredoxin-like activity . In: The Journal of Biological Chemistry . tape 265 , no. 16 , June 5, 1990, ISSN 0021-9258 , pp. 9114-9120 , PMID 2188973 .
- ↑ Bonney Wilkinson, Hiram F. Gilbert: Protein disulfide isomerase . In: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics . tape 1699 , no. 1 , June 1, 2004, ISSN 1570-9639 , p. 35-44 , doi : 10.1016 / j.bbapap.2004.02.017 .