Characterization of binding sites for diisopropyl phosphorofluoridate in spinal cord cytosol

Gel filtration chromatography was performed on cytosol preparation of hen spinal cord to find molecular target(s) for organophosphorus-induced delayed neurotoxicity (OPIDN). Three binding peaks of [(3)H]diisopropyl phosphorofluoridate (DFP), an organophosphate that induces OPIDN, were separated from the cytosol preparation. The activities of acetylcholinesterase (AChE) and neuropathy target esterase (NTE) that has been proposed as a screening method for OPIDN eluted in the fractions within these two DFP binding peaks. However, the other peak had none of the activities of AChE and NTE. Therefore, this DFP binding proteins in cytosol may be peculiar to the pathogenesis of OPIDN.