Influence of structural and physical properties of the thylakoid membrane on QA (-) oxidation.

Using isolated pea thylakoids, the relative rate of QA (-) oxidation has been estimated under various conditions, from the restoration of the induction curves following a dark period and from light 1-induced changes in modulated chlorophyll fluorescence excited by light 2.Alterations of QinfA (sup-) oxidation rates were observed under conditions which affected the degree of thylakoid stacking, the lipid fluidity and the integrity of the membranes. The results are discussed in terms of the interactions between QA (-) and the plastoquinone pool with particular emphasis on lateral diffusion.