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Reduction of protein disulfide bonds in an oxidizing environment
Author(s) -
Majoul Irina,
Ferrari David,
Söling Hans-Dieter
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(96)01447-0
Subject(s) - oxidizing agent , disulfide bond , chemistry , reduction (mathematics) , biochemistry , organic chemistry , geometry , mathematics
Following retrograde transport to the endoplasmic reticulum (ER) the A‐subunit of cholera toxin (CTX‐A) is partially cleaved into CTX‐A1 and CTX‐A2 by reduction of a disulfide bridge [Majoul et al. (1996) J. Cell Biol. 133, 777–789], although the redox state in the ER favors disulfide formation. We show here that the disulfide bridge of CTX‐A is cleaved in vitro already at GSH/GSSG ratios between 1 and 3. Protein disulfide isomerase (PDI) exerts only a minor accelerating effect. Various mixed disulfide intermediates (CTX‐A1‐S‐S‐CTX‐A1; PDI‐S‐S‐A2; PDI‐S‐S‐A1) appear during CTX‐A reduction. These results indicate that in the ER protein disulfide formation and protein disulfide reduction can take place simultaneously.