Phosphate translocator and adenylate translocator in chromoplast membranes

Abstract

It is shown by the criteria of saturation kinetics, specificity, and inhibition experiments that chromoplast membranes from the daffodil flower contain a phosphate translocator for the counter-exchange of phosphate, and 3-phosphoglycerate, as well as phosphoenolpyruvate; they also contain an adenylate translocator. This is the first report on the occurrence of these translocators in non-green plastids. Both translocators exhibit certain dissimilar properties when compared to the corresponding systems of chloroplasts. The transport rates of both translocators are sufficient to allow a prominent fatty acid synthesis in isolated chromoplasts when C3 intermediates of the glycolytic pathway or adenine nucleotides are used as energy sources.