1] Energetics of proton transport and secondary transport

Abstract

Publisher Summary This chapter discusses energetics of proton transport and secondary transport. Proton pumps and their associated proton-coupled transport systems are the most common biological systems of energy conversion. In describing the energetics of these systems, it is useful to distinguish between primary active transport systems or pumps, in which transport of an ion is directly coupled to a chemical (or photochemical) reaction, and secondary active transport systems, in which the vectorial transport of ions is coupled to the transport of other ions and substrates. The existence of several primary and secondary active transport systems which share common ions and substrates in the same membrane leads to complex energy conversion pathways. This chapter discusses the energetics of individual transport systems. However, as it is not always possible to study the energetics of a totally isolated system (except perhaps in a reconstituted system) the existence and the activity of other systems in the same membrane must be accounted for in a quantitative description of the energetics of primary and secondary transport.