Studies of a Biological Energy Transducer

Abstract

In much the same way that the double helix model of DNA has provided the backbone for molecular genetics, the chemiosmotic hypothesis formulated and refined by Peter Mitchell during the 1960s (Mitchell, 1961, 1963, 1966) is now the conceptual framework for a wide variety of bioenergetic phenomena. In its most general form (Fig. 1), the chemiosmotic concept postulates that the immediate driving force for many processes in energy-coupling membranes is a H⁺ electrochemical gradient ($Delta \overline \mu _{H^ + }$ ) composed of electrical and chemical parameters according to the following relationship: $Delta \overline \mu _{H^ + } /F = \Delta \psi - 2.3RT/F \Delta pH$ where Δψ represents the electrical potential across the membrane and the ΔpH is the chemical difference in H⁺ concentration across the membrane (R is the gas constant, T is absolute temperature, F is the Faraday constant; 2.3RT/F is equal to 58.8 at room temperature) (Mitchell, 1961).