Mechanism of inhibition of cholinesterases by Huperzine A. (Reannouncement with new availability information)
Huperzine A, an alkaloid isolated from Huperzia serrata was found to reversibly inhibit acetylcholinesterases (EC 3.1.7) and (EC 3.1.1.8) with i 3.1 on- and off-rates that depend on both the type and the source of enzyme. Long incubation of high concentrations of purified (1-8 PM) with huperzine-A did not show any chemical modification of huperzine-A. A low dissociation constant K sub 1 was obtained for mammalian acetylcholinesterase-huperzine (20-40 nM) compared to mammalian butyrylcholinesterase-huperzine (20-40 microns.) This indicates that the thermodynamic stability of huperzine-cholinesterase complex may depend on the number and type of aromatic amino acid residues in the catalytic pocket region of the cholinesterase molecule.
- Research Organization:
- Walter Reed Army Inst. of Research, Washington, DC (United States)
- OSTI ID:
- 177463
- Report Number(s):
- AD-A-254440/1/XAB; TRN: 60110427
- Resource Relation:
- Other Information: PBD: 30 Apr 1992
- Country of Publication:
- United States
- Language:
- English
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