Differences in conformational stability between native and phosphorylated acetylcholinesterase as evidenced by a monoclonal antibody.
Monoclonal antibody 25B1 generated against diisopropyl phosphorofluoridate inhibited fetal bovine serum acetylcholinesterase has been extensively characterized with respect to its anticholinesterase properties. This antibody demonstrated considerably different properties from previously reported inhibitory antibodies raised against acetylcholinesterase in terms of the degree of inhibition (greater than 98%), the high degree of specificity, and the stability of the antigen-antibody complex. Monoclonal antibody 25B1 appears to be directed against a conformational epitope located in close proximity to the catalytic center of the enzyme and was found to be most suitable for studying the stabilization of the active site of acetylcholinesterase against denaturation by heat or guanidine following phosphorylation by organophosphorus anticholinesterase compounds. This approach allowed the determination of stability rank order of various phosphorylated acetylcholinesterases. Among all the organophosphates tested, the combination of a methyl group and a negatively charged oxygen attached to the P atom, CH3P(O)(O-)-AChE, conferred the greatest protection to the active site of aged or nonaged organophosphoryl conjugates of acetylcholinesterase.
T10 T11 T12 T13 T14 T15 T16 T1 T2 T3 T4 T5 T6 T7 T8 T9
GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-N GENE-Y CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL GENE-Y GENE-Y
anticholinesterase acetylcholinesterase acetylcholinesterase anticholinesterase bovine serum acetylcholinesterase phosphorylated acetylcholinesterases phosphorylated acetylcholinesterase oxygen P CH3P(O)(O-) organophosphoryl diisopropyl phosphorofluoridate guanidine organophosphates AChE acetylcholinesterase