Novel protein targets for organophosphorus compounds

Inhibition of tritiated di-isopropyl phosphorofluoridate labelling by a ran ge of organophopshorus compounds was used to screen for novel OF-reactive t argets in rat-brain homogenates. Analysis of target proteins was conducted by SDS/PAGE and detection of tritiated proteins using a thin layer chromato graphy (TLC) linear analyser. Two major sites of H-3-DFP labelling were fou nd with relative molecular masses of 30 and 85 kDa. Rates of reaction of th ese labelling sites with a range of OP compounds were compared to that of a cetylcholinesterase. The 30 kDa band was found to be more sensitive to para oxon, dichlorvos and diazoxon than acetylcholinesterase. The 85 kDa band wa s found to be more sensitive to dichlorvos and diazoxon than acetylcholines terase. Neither labelling band reacted with chlorfenvinphos or demeton-s-me thyl at significant rates. (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.