UPTAKE AND PHOSPHORYLATION OF EXOGENOUS SUBSTRATES IN ANKISTRODESMUS BRAUNII .I. PARTICIPATION OF POLYPHOSPHATES IN UPTAKE OF GLUCOSE AND 2-DESOXY-GLUCOSE IN DARK AND IN LIGHT

1. Like other photosynthesizing organisms which have been investigated, Ankistrodesmus braunii absorbs more glucose from the surrounding medium in the light than in the dark. 2. When the algae are incubated with glucose and 32P-labelled orthophosphate in short-time-experiments, the TCA-soluble organic phosphate fraction is markedly increased. No such effect is seen when 2-desoxy-glucose is administered to the algae instead of glucose. 3. In pre-labelled algae glucose causes an increase in the TCA-soluble acid-stable organic P-fraction which shows light-dependent saturation kinetics. In such experiments 2-desoxyglucose causes a linear increase in the acid-stable organic P-fraction which shows no light dependence. 4. DCMU and Antimycin A when given together block oxidative as well as light phosphorylation. These compounds do not, however inhibit the increase in the sugar-P-fraction caused by 2-desoxy-glucose in 32P-labelled algae. 5. The increase in the sugar-32P after administration of substrates to the algae is accompanied by a decrease in the fraction of the polyphosphates C" and/or "D". 6. These results are explained by assuming that an inorganic polyphosphate-glucose-phosphotransferase is active in Ankistrodesmus braunii. © 1968 Springer-Verlag."