The β subunit of the high-conductance calcium-activated potassium channel contributes to the high-affinity receptor for charybdotoxin

摘要

Transient expression of either α or α+β subunits of the high-conductance Ca~2+-activated K~+ (maxi-K) channel has been achieved in COS-1 cells. Expression has been studied using charybdotoxin (ChTX), a peptidyl inhib- itor that binds in the pore on the subunit. Although some properties of monoiodotyrosine-ChTX (~125I-ChTX) binding to membranes derived from each type of transfected cells appear to be identical, other parameters of the binding reaction are markedly different.