Only three peptides proved suitable for LiP (Table ), and none showed evidence of differential proteolytic susceptibility following propachlor treatment (Figure ). While this indicates that the protein as a whole is not destabilized, it does not exclude the possibility that unprofiled regions of the protein might be affected. Protein destabilization can lead to both gain-of-function (toxic conformations) and loss-of-function. GAPDH activity has previously been shown to decrease in response to methylglyoxal and copper exposures, presumably due to conjugate and oxidation respectively . GAPDH modification can further lead to misfolding and aggregation . We evaluated GAPDH activity in cells treated with propachlor.