Reactive specificity of soman binding site

When organic phosphorus compouds, pyridines. methylcarbamates, alkylam-moniums and sulfonylfluorides were cormpared with pinacolyl methyl phosphonofluoridat-(soman) on the AChE-inactivated earthworm dorsal longituainal muscles, we found that only isopropylmethyl phosphonofluoridate, diethyl-4-nitrophenyl phosphate, O-ethyl-S-(2-diiso-proylaminoethyl)methylphosphonothiolate and S-trifluoromethyl-O,O'-dimethylDhosphoro-thiolate of the organic phosphates (or phosphonates) and l,1'-dimethyl 4,4'-bipyridylium of the pyriaines had tne soman-like muscular contractive effects which were abolishea by treating with l% Triton X-1OO, O.7% lubrol or 0.7% sodium desoxycholate, 20 oC, 30 min, pH 8.3, but in contrast, ACh effect remaincd unchanged. It appears that the ligand-specificity of soman binding site differs from that of ACh receptor and AChE.