Regulation of glycolytic rate in Streptococcus sanguis grown under glucose-limited and glucose-excess conditions in a chemostat.
The biochemical mechanisms of the acidogenic potential of Streptococcus sanguis ATCC 10556 grown in glucose-excess and glucose-limited continuous culture were studied. The rate of acid production during the glucose metabolism by the cells grown under glucose limitation (glucose-limited cells) was 2.1 to 2.6 times that by the cells grown in an excess of glucose (glucose-excess cells). When the glucose-limited cells were metabolizing glucose, intracellular concentrations of glucose 6-phosphate, fructose 6-phosphate, 3-phosphoglycerate, and pyruvate were higher, and that of glyceraldehyde 3-phosphate was lower, than those when the glucose-excess cells were metabolizing glucose. The levels of fructose 1,6-bisphosphate and dihydroxyacetone phosphate were not significantly different between these cells. The activities of glucose-phosphoenolpyruvate phosphotransferase system in decriptified cells and glyceraldehyde-3-phosphate dehydrogenase in cell-free extracts of the glucose-limited cells were higher than those in the glucose-excess cells. The activities of glucokinase, phosphoglycerate kinase, and pyruvate kinase in cell-free extracts of these cells were not different significantly. We conclude that the high glycolytic activity of the glucose-limited cells results from the increase in the synthesis of glucose-phosphoenolpyruvate phosphotransferase and glyceraldehyde-3-phosphate dehydrogenase.
D003470:Culture Media; D005941:Glucokinase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006019:Glycolysis; D007700:Kinetics; D010735:Phosphoglycerate Kinase / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D013298:Streptococcus sanguis / Q000254:growth & development / Q000378:metabolism*
D003470:Culture Media; D005954:Glucosephosphate Dehydrogenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D005941:Glucokinase; D011770:Pyruvate Kinase; D010735:Phosphoglycerate Kinase; D005947:Glucose