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

Using isolated pea thylakoids, the relative rate of Q_A^- 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 Q_A^- and the plastoquinone pool with particular emphasis on lateral diffusion.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - EDTA Ethylenediaminetetracetate - Hepes N-2-hydroxyethyl piperazine-N-2-ethanesulphonic acid - NADP nicotinamide adenine dinucleotide phosphate