Recent reports implicate the glycolytic enzyme, glyceraldehyde-3-phosophate dehydrogenase (GAPDH) in neuronal cell death. In the case of GAPDH, the mechanism of cell death involves oxidative stress and disulfide-bonded GAPDH aggregates. We observed greatly enhanced cysteine oxidation of both mammalian brain tubulin and rabbit muscle GAPDH by H2O2 in vitro when both proteins were present relative to when each individual protein was oxidized. We will provide evidence to support our hypothesis that the cysteines of one protein may be oxidized by H2O2 and then undergo thiol/disulfide exchange with a cysteine on the other resulting in enhanced oxidation of each and transient disulfides between them. The addition of high salt decreases the extent of oxidation of each protein by H2O2 suggesting an ionic interaction between tubulin and GAPDH facilitates oxidation. The effects of each protein, in both its oxidized and reduced forms, on the other's activity will also be presented.

Redox reactions between cysteines of tubulin and glyceraldehyde-3-phosphate dehydrogenase: Implications for oxidative stress and neurodegeneration

242nd National Meeting (2011)

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