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Pancreas specific protein disulfide isomerase, PDIp, is in transient contact with secretory proteins during late stages of translocation
Author(s) -
Volkmer Jörg,
Guth Silvia,
Nastainczyk Wolfgang,
Knippel Peter,
Klappa Peter,
Gnau Volker,
Zimmermann Richard
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00288-3
Subject(s) - protein disulfide isomerase , microsome , glycoprotein , biochemistry , secretory protein , isomerase , chemistry , chromosomal translocation , enzyme , biology , secretion , gene
Protein disulfide isomerase (PDI) and an additional lumenal protein of dog pancreas microsomes were previously observed to be in transient contact with secretory proteins during late stages of their co‐ or posttranslational translocation into these mammalian microsomes. The second protein was characterized as a 57 kDa glycoprotein. Here we identified this glycoprotein as the canine equivalent of human PDIp, a protein which was recently described as a new protein disulfide isomerase which is highly expressed in human pancreas. Canine PDIp is also a very abundant protein, its concentration in pancreatic microsomes approaches the concentration of PDI and of the major microsomal molecular chaperones. Apparently, PDIp shares with PDI not just the enzymatic but also the polypeptide binding or chaperoning activity. Furthermore, we suggest that PDIp, too, can be involved in completion of cotranslational as well as posttranslational translocation of proteins into mammalian microsomes.