The model also predicts that the decay in the voltage across the membrane following an intense current pulse of short duration (≈50 nsec) can be described by the sum of two exponentials. The model predicts a single exponential decay of the current in a voltage-clamp experimetn. These parameters and our model describe our kinetic experiments if we assume that the protonation reactions, which occur at the interfaces, remain at equilibrium. From these equilibrium and steady state measurements on diphytanoyl phosphatidylcholine/chlorodecane membranes we found that β A= β HA=1.4 10 -3cm, k A=175 s −1 and k HA=12,000 sec −1. These parameters were determined by equilibrium dialysis, electrophoretic mobility, membrane potential, membrane conductance, and spectrophotometric measurements. Four parameters characterize this model: the adsorption coefficients of the anionic and neutral forms of the weak acid onto the interface ( β A and β HA) and the rate constants for the movement of A − and HA across the membrane ( k A and k HA). We demonstrate that a simple kinetic model describes the transport of protons across lipid bilayer membranes by the weak acid CCCP (carbonyl cyanide m-chlorophenylhydrazone).

What is cccp in biochem