Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Journal of neurochemistry
23 (1974), S. 0
ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
—The effects of various cations and cholinergic ligands on the rate of α-bungarotoxin-acetylcholine receptor complex formation has been studied by means of a DEAE-cellulose disk assay technique. The reaction rate is reduced to one half the initial rate in the presence of 2·5 · 10−6m acetyleholine. a value close to the observed KD of ACh measured by equilibrium dialysis. Inhibition constants of about 5 mM were obtained for most monovalent cations whereas divalent cations gave inhibition constants of 0·05-0·2 mm. The rate and extent of toxin-receptor complex formation was also investigated as a function of hydrogen ion concentration; the rate of formation reaches a maximum at pH 7·5 and a group with a pK about 6 inhibits toxin binding to the receptor when protonated.These data can be correlated with the observed effects of inorganic cations on the binding of cholinergic ligands in vivo at the neuromuscular junction. Given the affinities of the individual cations, it is possible to predict how the apparent affinity of a cation-sensitive cholinergic ligand will change with variations of buffer composition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1974.tb04383.x
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