title: Study of the peptidasic site of cholinesterase: preliminary results.
abstract: The peptidasic site of highly purified human plasma cholinesterase was investigated using active-site-directed inhibitors. Peptidase activity was assayed taking substance P as substrate. Inhibition by organophosphates indicated that the peptidasic site contained an active serine. The presence of essential histidine residues associated with serine was revealed by histidine modifications. Carboxyl group reagents showed that the active centre contained carboxyl groups in a non-polar environment. The removal of sialic acids did not alter peptidase activity. The peptidasic site of cholinesterase shared many properties with serine proteases sites and esteratic sites of cholinesterases. In addition, with the peptidasic site, as well as the esteratic site, there was always the possibility of 'aging' when inhibited by DFP or soman.
authors.forename: A
authors.initials: A
authors.lastname: Chatonnet
authors.forename: P
authors.initials: P
authors.lastname: Masson
mesh_terms: D001665:Binding Sites / Q000187:drug effects; D002091:Butyrylcholinesterase / Q000097:blood*; D002800:Cholinesterase Inhibitors; D002802:Cholinesterases / Q000097:blood*; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D006639:Histidine; D006801:Humans; D007531:Isoflurophate / Q000494:pharmacology; D009439:Neuraminidase / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000378:metabolism*; D011804:Quinolines / Q000494:pharmacology; D012694:Serine; D012999:Soman / Q000494:pharmacology; D013373:Substance P / Q000378:metabolism; D014107:Tosyllysine Chloromethyl Ketone / Q000494:pharmacology
chemical_list: D002800:Cholinesterase Inhibitors; D009943:Organophosphorus Compounds; D011804:Quinolines; D007531:Isoflurophate; D014107:Tosyllysine Chloromethyl Ketone; D013373:Substance P; D012694:Serine; D006639:Histidine; C000470:EEDQ; D012999:Soman; D002091:Butyrylcholinesterase; D002802:Cholinesterases; D009439:Neuraminidase; D010447:Peptide Hydrolases; D004047:Diethyl Pyrocarbonate