Institute for Plant Biology, University of Zürich, Zollikerstr. 107, CH - 8008 Zürich Switzerland
Abstract:
Oxidative phosphorylation was measured in isolated energy-transducing membranes of the thermophilic cyanobacterium Mastigocladus laminosus with NADH-mediated electron transport. This dark phosphorylation was similar to photophosphorylation in its sensitivity to uncouplers and energy-transfer inhibitors. However, photophosphorylation was 20- to 50-times more active than oxidative phosphorylation. The ratio of oxidative phosphorylation was about 0.2. Besides oxidative phosphorylation, adenylate kinase- and ADP-Pi exchange activity were measured in the dark. The ADP-Pi exchange reaction was identified as polynucleotide phosphorylase.