Rapid transport of protons across membranes by aliphatic amines and acids

Abstract

The pH gradient generated across membranes can be dissipated efficiently by means of a single-turnover cycle of aliphatic amines and acids present in the membrane. The kinetics of this single-turnover process was in the submillisecond time scale and was measured by creating pH gradients (Δ pH) using a temperature jump. The observed Δ pH decay process was identified as due to rapid transmembrane movement of the neutral form of either the acid or the amine. The rate constant was estimated to be in the range (1-6) × 10³ s^-1 in the case of aliphatic amines.