Destabilization and denaturation of cellular protein by glutathione depletion.

Freeman ML, Huntley SA, Meredith MJ, Senisterra GA, Lepock J
Cell Stress Chaperones. 1997 2 (3): 191-8

PMID: 9314607 · PMCID: PMC312997 · DOI:10.1379/1466-1268(1997)002<0191:dadocp>;2

This investigation tested the hypothesis that depletion of intracellular glutathione, in contrast to its oxidation could lead to non-native oxidation of protein thiols, thereby trapping proteins in an unstable conformation. Chinese hamster cells were exposed to the alpha, beta-unsaturated dicarboxylic acid diethylmaleate in order to produce rapid glutathione (GSH) depletion without oxidation. Measurement of the fluorescence of oxidized 2',7'-dichlorofluorescein diacetate indicated that reactive oxygen species accumulated in GSH depleted cells. Glutathione depletion was found to alter protein thiol/disulfide exchange ratios such that 17 to 23 nmol of protein SH/mg protein underwent oxidation. Differential scanning calorimetry (DSC) of glutathione depleted cells yielded a profile of specific heat capacity versus temperature that was characteristic of cells containing destabilized and denatured protein. In addition, cells depleted of glutathione exhibited a two-fold increase in NP-40 insoluble protein. These results indicate that depletion of intracellular glutathione caused oxidation of protein thiols, protein denaturation and aggregation and provide a mechanism to explain how GSH depletion can initiate stress responses.

MeSH Terms (10)

Animals CHO Cells Cricetinae Glutathione Intracellular Fluid Oxidation-Reduction Protein Denaturation Proteins Reactive Oxygen Species Sulfhydryl Compounds

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