{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,19]],"date-time":"2025-09-19T10:44:05Z","timestamp":1758278645981},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1980,2,1]],"date-time":"1980-02-01T00:00:00Z","timestamp":318211200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[1980,2]]},"abstract":"<jats:p>1. Binding of a purified scorpion toxin to membrane fragments isolated from electroplaque of an electric eel <jats:italic>Electrophorus electricus<\/jats:italic> was studied using a radio\u2010iodinated toxin.<\/jats:p><jats:p>2. A scorpion toxin was purified from the venom of <jats:italic>Leiurus quinquestriatus<\/jats:italic> and iodinated with <jats:sup>125<\/jats:sup>I in a lactoperoxidase\u2010catalysed reaction. Monoiodinated toxin, isolated by an ion exchange chromatography, retarded the inactivation kinetics of Na current to a similar extent as the native toxin, indicating that radioiodination did not appreciably affect physiological and binding properties of the native toxin.<\/jats:p><jats:p>3. Analyses of binding properties by Scatchard plots showed the presence of two classes of binding sites (with low and high affinities) in the membrane preparation from eel electroplaque; similar preparation from an electric skate, of which the electroplaque is known to be devoid of Na channels, possessed only the low affinity sites.<\/jats:p><jats:p>4. The number of high affinity sites in the eel preparation was 41\u00b78 \u00b1 10\u00b75 p\u2010mole\/g tissue; the value was within the range reported for tetrodotoxin binding to similar preparations (15\u2010148 p\u2010mole\/g tissue).<\/jats:p><jats:p>5. A variety of cations (Na<jats:sup>+<\/jats:sup>, Mn<jats:sup>2+<\/jats:sup> and La<jats:sup>3+<\/jats:sup>) inhibited the high affinity scorpion toxin binding, as indicated for the toxin binding to Na channels by a previous electrophysiological study. <jats:italic>K<\/jats:italic><jats:sub>D<\/jats:sub> value in the presence of 120 m\n<jats:sc>M<\/jats:sc>\u2010Na<jats:sup>+<\/jats:sup> (approx. 8 n\n<jats:sc>M<\/jats:sc>) agreed reasonably with that (approx. 10n\n<jats:sc>M<\/jats:sc>) reported for the scorpion toxin binding to excitable neuroblastoma cells or synaptic nerve ending particles under conditions where membrane potential was depolarized by the addition of 135 m\n<jats:sc>M<\/jats:sc>\u2010KCl.<\/jats:p><jats:p>6. Pretreatment of the eel membrane preparation with \u03b2\u2010bungarotoxin (7\u201044 ng\/ml.) in the presence of Ca ions (10\u2010200 \u03bc\n<jats:sc>M<\/jats:sc>) resulted in a substantial loss of high affinity binding of scorpion toxin. When phospholipase A<jats:sub>2<\/jats:sub> activity of the \u03b2\u2010toxin was inactivated by a chemical modification with <jats:italic>p<\/jats:italic>\u2010bromophenacyl bromide, the inhibitory action of the \u03b2\u2010bungarotoxin was abolished.<\/jats:p><jats:p>7. It is concluded that a high affinity binding of scorpion toxin to the eel electroplaque membrane fragments represents the binding to Na channels <jats:italic>in vitro<\/jats:italic>, and that phospholipase A<jats:sub>2<\/jats:sub> activity of \u03b2\u2010bungarotoxin interferes with the binding of scorpion toxin to Na channels.<\/jats:p>","DOI":"10.1113\/jphysiol.1980.sp013139","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T07:24:23Z","timestamp":1418973863000},"page":"507-520","source":"Crossref","is-referenced-by-count":13,"title":["Binding of scorpion toxin to sodium channels <i>in vitro<\/i> and its modification by \u03b2\u2010bungarotoxin"],"prefix":"10.1113","volume":"299","author":[{"given":"Harumasa","family":"Okamoto","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[1980,2]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1980.sp013139","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1980.sp013139","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,11,5]],"date-time":"2023-11-05T17:07:00Z","timestamp":1699204020000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1980.sp013139"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1980,2]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1980,2]]}},"alternative-id":["10.1113\/jphysiol.1980.sp013139"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1980.sp013139","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1980,2]]}}}