High affinity binding of [125I]monoiodoapamin to isolated guinea-pig hepatocytes.
The bee venom neurotoxin apamin has been labelled with 125I and its binding to isolated guinea-pig hepatocytes measured under physiological conditions. A single saturable component of [125I]monoiodoapamin binding with a Kd of 350 pM and Bmax of 0.99 fmol/mg dry wt was identified. Native apamin displaced labelled apamin with a Kd of 376 pM which is broadly in keeping with the concentrations found to inhibit K loss from guinea-pig hepatocytes. These observations, together with the binding found in other tissues, suggest that specific binding of labelled apamin is particularly associated with apamin-sensitive, Ca-activated K-channels.
D000818:Animals; D001030:Apamin / Q000031:analogs & derivatives / Q000378:metabolism*; D001514:Bee Venoms / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels; D011956:Receptors, Cell Surface / Q000378:metabolism
D001514:Bee Venoms; D015221:Potassium Channels; D011956:Receptors, Cell Surface; C033799:apamin receptor; D001030:Apamin; C033900:monoiodoapamin; D011188:Potassium