caa a22 4500 397556349 CHVBK 20180308164803.0 cr unu---uuuuu 161202e199609 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021445 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021445 A Role of PDI in the Reductive Cleavage of Mixed Disulfides [Elektronische Daten] [Shun-ichi Nakamura, Massaki Matsushima, Haiwei Song, Masakazu Kikuchi] We previously reported that protein disulfide isomerase (PDI) can dissociate the glutathione molecule in vitro from the mutant human lysozyme (hLZM) C77A-a, which is modified with glutathione at Cys95; however, it seems structurally difficult for PDI to attack either the disulfide bond or the side chain of the cysteine residue of a mixed disulfide. To investigate the function of PDI, we introduced several glutathione and cysteine derivatives at Cys95, instead of the glutathione of C77A-a. Using thiol compounds modified by 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB), we could easily modify the free thiol group of CI7A-b (C77A with no glutathionylation), without denaturation. For all of the modifications we tested, a negative correlation was found between the initial rate and the acceleration ratio of the reductive cleavage of mixed disulfides with PDI. A mutant PDI (hPDIM), which has no thiol-disulfide exchange activity, suppressed the reductive cleavage of the mixed disulfide of C77A-a with hPDI, suggesting that hPDI non-covalently interacted with the substrates. Taking account of the results of the structural analysis, we conclude that one of the functions of PDI in vivo lies in relaxing the structure around the disulfide bond, as well as in exchanging the thiol-disulfide bonds. © 1996 BY THE JOURNAL OF BIOCHEMISTRY Regular Papers nationallicence glutathione nationallicence human lysozyme nationallicence protein disulfide isomerase nationallicence protein folding nationallicence reductive cleavage of disulfide bond nationallicence Nakamura Shun-ichi Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut Matsushima Massaki Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut Song Haiwei Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut Kikuchi Masakazu Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut The Journal of Biochemistry Oxford University Press 120/3(1996-09), 525-530 0021-924X 120:3<525 1996 120 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021445 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021445 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nakamura Shun-ichi Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut NATIONALLICENCE 700 1- Matsushima Massaki Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut NATIONALLICENCE 700 1- Song Haiwei Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut NATIONALLICENCE 700 1- Kikuchi Masakazu Protein Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 120/3(1996-09), 525-530 0021-924X 120:3<525 1996 120 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford