Influence of voltage and ATP on ion-channel of (Na,K)ATPase incorporated into solvent-free phospholipid planar bilayers.
Purified (Na,K)ATPase was incorporated into solvent free phospholipid bilayers made on patch-clamp pipettes. In the absence of ATP, the incorporated enzyme acted as an ion-channel which underwent opening and closing (switching) upon application of transmembrane potential gradient of more than 40 mV. The minimum conductance was about 40 pS. It was inhibited by ouabain from one side. ATP added to the opposite side shifted the threshold potential for switching of the channel to 80 mV. Furthermore the magnitude of minimum conductance decreased to 6-10 pS in the presence of ATP.
N
N
Kumazawa
T
T
Tsujimoto
Y
Y
Fukushima
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D004553:Electric Conductivity; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008051:Lipid Bilayers / Q000378:metabolism*; D008564:Membrane Potentials; D010042:Ouabain / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007473:Ion Channels; D008051:Lipid Bilayers; D010042:Ouabain; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase