Characterization and partial purification from pheochromocytoma cells of an endogenous equivalent of scyllatoxin, a scorpion toxin which blocks small conductance Ca(2+)-activated K+ channels.
This work describes the partial purification of a heat-stable peptide which has the same properties as the scorpion toxin, scyllatoxin, a specific blocker of one class of Ca(2+)-activated K+ channels: (i) it competes with [125I]apamin for binding to the same site, (ii) like apamin and scyllatoxin, it blocks the after-potential hyperpolarization in skeletal muscle cells in culture, (iii) like apamin and scyllatoxin, it contracts guinea-pig taenia coli relaxed by epinephrine, (iv) it cross-reacts with antibodies raised against scyllatoxin but not with antibodies raised against apamin.
Auguste
P
P
Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France.
Hugues
M
M
Borsotto
M
M
Thibault
J
J
Romey
G
G
Coppola
T
T
Lazdunski
M
M
D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D001030:Apamin / Q000037:antagonists & inhibitors / Q000378:metabolism; D001667:Binding, Competitive / Q000502:physiology; D002118:Calcium / Q000502:physiology*; D004553:Electric Conductivity; D010450:Endopeptidases; D006358:Hot Temperature; D016716:PC12 Cells; D015221:Potassium Channels / Q000187:drug effects*; D011863:Radioimmunoassay; D017981:Receptors, Neurotransmitter / Q000378:metabolism; D012604:Scorpion Venoms / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology*
D015221:Potassium Channels; D017981:Receptors, Neurotransmitter; D012604:Scorpion Venoms; C033799:apamin receptor; C056574:leiurotoxin I; D001030:Apamin; D010450:Endopeptidases; D002118:Calcium