Energy conversion and changes in physical parameters in chloroplasts and subchloroplast particles II. Energy conversion in chloroplasts and different types of subchloroplast particles

概要

論文の詳細を見る
The light-induced absorbance change at 515 nm, light-induced hydrogen ion uptake and ATP formation were compared in chloroplasts and different types of sonicated subchloroplast particles. No parallel relationship among the activities for ATP formation, hydrogen ion uptake and the 515-nm change was observed in different types of preparations. NH_4Cl inhibited ATP formation in chloroplasts but had little effect on subchloroplast particles. In contrast, the light-induced hydrogen ion uptake was inhibited by NH_4Cl in a similar manner. Tetraphenylboron (TPB), at 1 μM, inhibited ATP formation by about 30% in both chloroplasts and subchloroplast particles. In the presence of TPB. ATP formation in chloroplasts was strongly inhibited by NH_4Cl, but in subchloroplast particles the addi-tional inhibitory effect of NH_4Cl was small. A synergistic inhibition of photophosphorylation by valinomycin plus NH_4Cl was much clearer. Although acceleration of the recovery of the 515-nm change by NH_4Cl or valinomycin was moderate, the 515-nm change virtually disappeared when NH_4Cl and valinomycin were added simultaneously. Although the membrane potential has a major role as the principal driving force for ATP formation in subchloroplast particles, the simultaneous abolishment of the pH gradient and membrane potential may be required to uncouple ATP formation.
日本植物生理学会の論文