Description_x000D_ General description_x000D_ Prolyl 4-hydroxylase subunit β (P4HB) or protein disulfide isomerase is a redox-regulated thiol-containing protein. The gene encoding this protein is localized on human chromosome 17q25.3._x000D_ Protein Disulfide Isomerase (PDI, Erp58) is an abundant multifunctional, soluble enzyme (E.C. 5.3.4.1) that resides in the lumen of the endoplasmic reticulum of eukaryotic cells. It consists of four tandem domains, two of which contain a catalytic site for disulfide bond formation. A mitochondrial isoform of PDI (approx. 54 kDa) has been recently described. PDI has an N-terminal endoplasmic reticulum (ER) signal and a C-terminal ER- retention KDEL signal sequences. PDI was found on the cell surface of several cell types including endothelial cells, platelets and hepatocytes._x000D_ Immunogen_x000D_ protein disulfide isomerase purified from bovine liver._x000D_ Application_x000D_ Anti-Protein Disulfide Isomerase antibody produced in rabbit has been used in immunoblotting, immunoprecipitation and immunofluorescence._x000D_ Physical form_x000D_ Solution in 0.01 M phosphate buffered saline, pH 7.4, containing 15 mM sodium azide._x000D_ Disclaimer_x000D_ Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals._x000D_ Biochem/physiol Actions_x000D_ Prolyl 4-hydroxylase subunit β (P4HB) or protein disulfide isomerase acts as a molecular chaperone in the endoplasmic reticulum of cells and also as an oxidoreductase. It associates with steroid hormones and modulates their actions, concentrations and storage. P4HB accelerates the formation of disulphide bonds in proteins and hence aids in their folding._x000D_ Protein Disulfide Isomerase (PDI) catalyzes the formation and rearrangements of both intrachain and interchain disulfide bonds in secreted proteins. It plays an important role in various cellular processes including cell adhesion. PDI has calcium-dependent transglutaminase activity and is involved in the catalysis of isopeptide bond formation. PDI participates in the hydroxylation of proline in procollagen during collagen synthesis and in the transfer of neutral lipid onto nascent lipoprotein particles. Estrogen binding by PDI has also been reported.