On the Interaction of ATP with the Energy Conservation System in Chloroplasts

Abstract

Reversal of various steps of the process of photophosphorylation has been detected using sensitive tests made with exchange reactions (SHAVIT et al 1967, BOYER 1967). However, regarding the metabolic significance of the reversal, the reaction is still considered essentially irreversible If dynamic reversal occurs, changes in ADP:ATP ratios or in the level of high energy intermediates may be expected to affect the rates of reactions involved. Indeed, ATP, ADP or P. were shown to affect the rates of exchange reactions (AVRON et al 1965, SKYE et al 1967). The rate of electron transport is also known to be stimulated in the presence of phosphoryl ating agents or decreased when all the ADP is phosphoryloated (AVRON et al 1958, GOOD I960). However, under normal reaction conditions, the rates of phosphorylation and electron transport were not affected by ATP (AVRON 1961).