Anionic subsites of the catalytic center of acetylcholinesterase from Torpedo and from cobra venom.
A peptide of acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, EC 3.1.1.7) from the venom of the cobra Naja naja oxiana labeled by the affinity reagent N,N-dimethyl-2-phenylaziridinium (DPA) has been identified. The sequence is Gly-Ala-Glu-Met-Trp-Asn-Pro-Asn. In AcChoEase from Torpedo californica, a homologous peptide was labeled and isolated. Its sequence is Ser-Gly-Ser-Glu-Met-Trp-Asn-Pro-Asn, representing positions 79 through 87. In both cases labeling can be prevented by 0.1 mM edrophonium, indicating that the respective peptides form part of the anionic subsite of the catalytic center. The modified residue was tryptophan (Trp-84 in Torpedo AcChoEase) in both enzymes. In contrast to AcChoEase from Torpedo, the enzyme from cobra venom does not contain a peripheral anionic binding site.
Kreienkamp
H J
HJ
Institut für Biochemie, Freie Universität Berlin, Federal Republic of Germany.
Weise
C
C
Raba
R
R
Aaviksaar
A
A
Hucho
F
F
D000110:Acetylcholinesterase / Q000378:metabolism*; D000345:Affinity Labels / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001388:Aziridines / Q000378:metabolism; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D004546:Elapid Venoms / Q000378:metabolism*; D004557:Electric Organ / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D011419:Propidium / Q000494:pharmacology; D012689:Sequence Homology, Nucleic Acid; D014101:Torpedo
D000345:Affinity Labels; D001388:Aziridines; D004546:Elapid Venoms; D010446:Peptide Fragments; C001054:N,N-dimethyl-2-phenylaziridinium; D011419:Propidium; D000110:Acetylcholinesterase