K+ conductance modified by a titratable group accessible to protons from the intracellular side of the squid axon membrane

Biophys J. 1979 May;26(2):319-24. doi: 10.1016/S0006-3495(79)85251-0.


In the range of pH examined (5.2-10), variations of internal pH from high to low values result in a reversible decrease of the conductance of the open K channels, without significantly affecting the kinetics parameters. A linear plot of the conductance versus internal pH suggests the existence of a titratable group that has an apparent pKa of about 6.9, and that is accessible to protons only from the intracellular side of the membrane.

MeSH terms

  • Animals
  • Axons / metabolism*
  • Cell Membrane / metabolism
  • Decapodiformes
  • Electric Conductivity
  • Hydrogen-Ion Concentration
  • Ion Channels / metabolism*
  • Kinetics
  • Potassium / metabolism*


  • Ion Channels
  • Potassium