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Updated: Aug 16, 2026

Purification of Hsp104, a Protein Disaggregase
Published on: September 30, 2011
Intrapolypeptide disulfides in human alphaA-crystallin and their effect on chaperone-like function
M Cherian-Shaw1, J B Smith, X Y Jiang
1Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100, USA.
Abstract:
We report studies on the role of protein-protein disulfides (PSSP) in the age-related loss of chaperone activity of alpha-crystallins. AlphaL-crystallin fraction was isolated from human lenses of different ages and the chaperone-like activity was determined before and after treatment with glutathione reductase (GR) and NADPH. The results confirmed an age-dependent decrease in chaperone-like function and significant improvement of this function by GR treatment. Electrospray ionization mass spectrometric (ESIMS) analysis of alphaA-crystallin suggested the presence of very little protein-glutathione mixed disulfides. ESIMS analysis of Asp-N digests of alphaA-crystallin revealed that nearly all the remaining portion of Cys-131 and Cys-142 of alphaA-crystallin was present in the form of intrapolypeptide disulfide bonds. These results show for the first time that predominantly disulfide bonds formed during aging contribute to the age-dependent loss in chaperone activity of alpha-crystallin in human lenses.
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