In this chapter, distortions of the α and β rate constants are examined. These distortions produce the increased time constants for potassium gates and for sodium inactivation gates. Sodium activation gates have negligible distortion (below V_1/2) and the rate constants α_m and β_e are considered equivalent to α_e and βe for electron tunneling. Most of the distortions are due to the voltage sensitivity of ion fluxes crossing energy barriers in the channel. The exception is the sodium inactivation gate, which apparently has an additional edge distortion due to the location of the tunnel track control site near the protein/cytoplasm interface.

Chapter Contents:

• 5.1 Sodium channel inactivation gate leakage
• 5.2 Ion channel gating
• 5.3 Inactivation gating and open-gate distortion
• 5.4 Sodium channel activation gates and distortion
• 5.5 Potassium channel gating and distortion
• 5.6 Edge distortion of inactivation gating
• 5.7 Multistate gating

Inspec keywords: sodium; molecular biophysics; bioelectric phenomena; sensitivity; tunnelling; reaction rate constants; potassium; proteins; cellular biophysics

Other keywords: electron tunneling; ion fluxes; time constants; gating factors; protein-cytoplasm interface; sodium inactivation gates; energy barriers; β rate constants; edge distortion; sodium activation gates; potassium gates; voltage sensitivity; distortion factors; α rate constants

Subjects: Measurements of chemical rate constants, reaction cross sections, and activation energies; Physics of subcellular structures; Physical chemistry of biomolecular solutions and condensed states; Bioelectricity; Biomolecular interactions, charge transfer complexes