Uptake and Utilization of Sugar Phosphates by Anabaena flos-aquae

Abstract

The effect of various sugar phosphates on CO₂ fixation in Anabaena flos-aquae was investigated and found to be very similar to that found for isolated spinach chloroplasts. One exception, glucose 6-phosphate, has a stimulatory effect on CO₂ fixation in Anabaena but not in isolated chloroplasts.

Further examination of the role of glucose 6-phosphate metabolism in Anabaena indicates that: (a) this sugar phosphate can be taken up; (b) its uptake is greater in the light than the dark; (c) turnover of glucose 6-phosphate is inhibited in the light; and (d) glucose 6-phosphate can support dark CO₂ fixation. These results are discussed with reference to photosynthesis-related control of glucose 6-phosphate metabolism and the role of glucose 6-phosphate as a source for reducing equivalents and ATP in blue-green algae.