The Effect of Antimycin a and 1:10 — Phenanthroline on Rapid h⁺-Uptake by Chromatophores from Rhodopseudomonas Spheroides

Abstract

The use of pH indicators and spectrophotometric methods has made it possible to measure rapid changes in pH associated with biochemical reactions of macromolecules (ANTONINI et al. 1963), mitochondria (CHANCE & MELA 1966, MITCHELL et al. 1966, SARIS & SEPPALA 1969), and bacterial chromatophores (COST & FRENKEL 1967, CHANCE et al. 1966, 1970,JACKSON & CROFTS 1969, CROFTS et al. 1970). Indicators of pH have a restricted range over which measurements can usefully be made, and this has limited the study of rapid H+-changes, especially in bacterial chromatophores.The range of useful indicators has been further limited by the observation that bromothymol blue used in earlier work (CHANCE & MELA 1 9 6 6, SARIS & SEPPALA 1969, COST & FRENKEL 1967), undergoes colourchanges associated with the degree of binding of the indicator, and that the binding alters with changes in the energetic state of the membrane system (MITCHELL et al. 1968, JACKSON & CROFTS 1969).