Purified scorpion toxin (Leiurus quinquestriatus) slows inactivation of sodium channels in frog muscle at concentrations in the range of 17-170 nM. Mono[125I]iodo scorpion toxin binds to a single class of sites in frog sartorius muscle with a dissociation constant of 14 nM and a binding capacity of 13 fmol/mg wet weight. Specific binding is inhibited more than 90% by 3 microM sea anemone toxin II and by depolarization with 165 mM K+. Half-maximal inhibition of binding is observed on depolarization to -41 mV. The voltage dependence of scorpion toxin binding is correlated with the voltage dependence of activation of sodium channels. Removal of calcium from the bathing medium shifts both activation and inhibition of scorpion toxin binding to more negative membrane potentials. The results are considered in terms of the hypothesis that activation of sodium channels causes a conformational change in the scorpion toxin receptor site resulting in reduced affinity for scorpion toxin.
Skip Nav Destination
Article navigation
1 September 1979
Article|
September 01 1979
Binding of scorpion toxin to receptor sites associated with sodium channels in frog muscle. Correlation of voltage-dependent binding with activation.
W A Catterall
Online ISSN: 1540-7748
Print ISSN: 0022-1295
J Gen Physiol (1979) 74 (3): 375–391.
Citation
W A Catterall; Binding of scorpion toxin to receptor sites associated with sodium channels in frog muscle. Correlation of voltage-dependent binding with activation.. J Gen Physiol 1 September 1979; 74 (3): 375–391. doi: https://doi.org/10.1085/jgp.74.3.375
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionSuggested Content
Kinetic analysis of the action of Leiurus scorpion alpha-toxin on ionic currents in myelinated nerve.
J Gen Physiol (November,1985)
Charybdotoxin blocks voltage-gated K+ channels in human and murine T lymphocytes.
J Gen Physiol (June,1989)
Sodium channels in presynaptic nerve terminals. Regulation by neurotoxins.
J Gen Physiol (September,1980)
Email alerts
Advertisement