Photoaffinity labeling of components of the apamin-sensitive K+ channel in neuronal membranes.
J Biol Chem
; 260(7): 3895-8, 1985 Apr 10.
Article
em En
| MEDLINE
| ID: mdl-2579943
ABSTRACT
An azidonitrophenylaminoacetyl mono[125I]iodoapamin derivative was prepared which showed specific binding to rat neuronal membranes. UV photolysis lead to the irreversible occupation of binding sites. Photo-labeling of intact primary cultured rat neurones followed by membrane solubilization, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography revealed the covalent incorporation of radioactivity into 3 main components with Mr = 86,000, 30,000, and 23,000. Labeling was completely prevented by a competing excess of native apamin. Similar studies on purified synaptic membranes from the rat brain showed another labeling pattern with major bands corresponding to Mr = 86,000 and 59,000. Although the reasons for the partial discrepancy between cultured embryonic neurons and an adult brain membrane fraction are not yet clear, we conclude that these proteins are intimately associated with the apamin binding site and are probably components of a type of Ca2+-activated K+ channel.
Buscar no Google
Base de dados:
MEDLINE
Assunto principal:
Apamina
/
Potássio
/
Venenos de Abelha
/
Canais Iônicos
/
Neurônios
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
/
Pregnancy
Idioma:
En
Ano de publicação:
1985
Tipo de documento:
Article