Chhajlani V

References (2)

Title : Novel allosteric sites on human erythrocyte acetylcholinesterase identified by two monoclonal antibodies - Olson_1990_Arch.Biochem.Biophys_277_361
Author(s) : Olson CE , Chhajlani V , August JT , Schmell ED
Ref : Archives of Biochemistry & Biophysics , 277 :361 , 1990
Abstract : Monoclonal antibodies against human erythrocyte acetylcholinesterase (acetylcholine acetylhydrolase EC 3.1.1.7) have been examined for inhibition of enzyme activity. Of sixteen antibodies analyzed, only one (C1B7) inhibited enzyme activity, indicating selection of an unusual susceptible site. The inhibitory activity of C1B7 was characterized and compared to another inhibitory antibody, AE-2, previously described by Fambrough et al. (Proc. Natl. Acad. Sci. USA 79, 1078, 1982). Maximal demonstrated inhibition was 84% for C1B7 and 72% for AE-2 and antibody inhibition of enzyme activity was equivalent for the reduced and alkylated acetylcholinesterase monomer and the intact dimer. The Ki (stoichiometry of the enzyme-antibody reaction estimated from enzyme kinetics) was 1.0 for C1B7 and 4.8 molecules of antibody per monomer of acetylcholinesterase for AE-2. The antibodies did not compete with one another for binding to acetylcholinesterase, indicating that they have different target epitopes on the enzyme. Antibody binding to the enzyme was not specifically affected by any of the anticholinesterase agents tested: (a) the irreversible esteratic site-directed inhibitor diisopropylfluorophosphate; (b) the reversible active site-directed inhibitors edrophonium, neostigmine, BW284c51, and carbachol; and (c) allosteric site-directed compounds propidium and gallamine. Kinetic analysis of their effects provide evidence that both antibodies decrease the catalytic rate of enzyme activity and have little or no effect on substrate binding.
ESTHER : Olson_1990_Arch.Biochem.Biophys_277_361
PubMedSearch : Olson_1990_Arch.Biochem.Biophys_277_361
PubMedID: 1689985

Title : Purification and partial amino acid sequence analysis of human erythrocyte acetylcholinesterase - Chhajlani_1989_FEBS.Lett_247_279
Author(s) : Chhajlani V , Derr D , Earles B , Schmell ED , August T
Ref : FEBS Letters , 247 :279 , 1989
Abstract : A single step immunoaffinity purification procedure for human erythrocyte acetylcholinesterase is described which permitted the isolation of milligram quantities of enzyme from 10 U of erythrocytes, with 113,000-fold purification and a yield of about 22%. In SDS-PAGE analysis, the enzyme corresponds to a disulfide linked dimer of 140 kDa which is converted to a 70 kDa monomer upon disulfide reduction. The tryptic peptides generated from purified enzyme were separated by reverse-phase HPLC. Five of these peptides were analysed to determine the amino acid sequences. The obtained sequences showed no homology to the already known amino acid sequences for human serum and brain butyrylcholinesterase and Torpedo californica acetylcholinesterase.
ESTHER : Chhajlani_1989_FEBS.Lett_247_279
PubMedSearch : Chhajlani_1989_FEBS.Lett_247_279
PubMedID: 2714437
Gene_locus related to this paper: human-ACHE