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1. The inference, implicit in the chemiosmotic hypothesis, that protons move into the bulk phase during ATP synthesis was investigated. 2. Incubation of rat liver mitochondria in the presence of the cation exchanger CM-Sephadex C-50 caused alkalinization in the medium, though total ATP synthesis remained unchanged. The addition of N-ethylmaleimide prevented the alkalinization, but there was still no indication of protons passing into the medium. The expected proton movement [Mitchell & Moyle (1967) Biochem. J. 105, 1147--1162] was readily detected when as an equivalent acid pulse. 3. Analysis of delta H+ decay curves after O2 pulses (3 micrograms-atoms of O/g of protein) indicated the presence of fast and slow components of decay, with first-order rate constants (k) of 0.24s-1 and 0.032s-1. The fast decay was finite and was eliminated in the presence of N-ethylmaleimide. 4. These observations are interpreted as evidence for the development of unmasking of fixed charges on the outer surface of the mitochondrial inner membrane during energization and for the existence of proton-retentive electrical fields (rho-zones) on this surface. The charge concentration is calculated as about 1 charge/10nm2. 5. A cycle of changes in a single fixed-charge molecule is proposed which mediates both Ca2+ uptake and the first step in the utilization of the rho-zone protonmotive force, delta p rho.

In a previous communication (Archbold et al., 1974) we have described experiments the results of which are not readily reconciled with some aspects of the chemiosmotic hypothesis. Our interpretation required a distinction between the distributive nature ofelectroneutral (EN) and eiectrogenic (EG) proton movements across the mitochondria1 inner membrane. This distinction has not been made hitherto in the formulation of the energy-transduction relationship. Mitchell (1968) debated, but ultimately disregarded, the significance of the double electrical layer on wi, the electrical potential in the mito

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This article will provide a framework for analysing unionist responses and reactions to the Northern Irish peace process. It identifies four responses to the Belfast Agreement that have reflected unionist divisions over the peace process: a principled yes position, a pragmatic yes, a pragmatic no and a principled no. However, these positions hide a common interpretation of the process in general and this interpretation is outlined. The article then seeks to understand why these different positions on the Agreement have emerged from this common narrative and it identifies how contextual factors and the actions of other political actors have done this. In doing so it uses an interpretative methodology and seeks to critique the dominant frameworks of analysis of the peace process and the Agreement.