[The effect of phospholipase D on photochemical activity and lipid composition of isolated spinach chloroplasts]

Phospholipase D shows short and longtime effects on photochemical activity of isolated spinach chloroplasts. After very short incubations with Phospholipase D (Pl D) the Ferricyanide reduction and Dichlorphenol-idenophenol reduction are 70% to 90% higher than in control chloroplasts. In uncoupled chloroplasts the reduction rates are about 20% higher than in the controls. After one h of incubation time with Phospholipase D the photochemical activity is inhibited and now shows only 40% of the control activity. The effect of Phospholipase D on uncoupled chloroplasts is somewhat lower. After two h of incubation time the control activity decreases to about 50% whereas the PLD-effected activity is reduced to 10% of the initial rates. Cyclic phosphorylation is inhibited by Phospholipase D, presumably because Phospholipase D exerts an uncoupling effect.