tokens: Such organophosphorus ( OP ) compounds as diisopropylfluorophosphate ( DFP ), sarin and soman are potent inhibitors of acetylcholinesterases ( AChEs ) and butyrylcholinesterases ( BChEs ). The acute toxicity of OPs is the result of their irreversible binding with AChEs in the central nervous system ( CNS ), which elevates acetylcholine ( ACh ) levels .