proton pump

:  a molecular mechanism that transports hydrogen ions across cell membranes The physiological essence of the proton pump is to exchange extracellular K⁺ for intracellular H⁺.—John E. Hoover, Remington: The Science and Practice of Pharmacy, 21st edition, 2005 Chemical gradients have been used to create asymmetry in the environment, as in the case of proton pumps to couple chemical energy with molecular motion.—Jay Siegel, Science, 7 Oct. 2005—called also acid pump