Identification of GTP as a physiologically relevant inhibitor of Escherichia coli ADP-glucose synthetase.
We show that physiological concentrations of GTP can significantly inhibit wild-type Escherichia coli ADP-glucose synthetase (the rate-limiting enzyme of bacterial glycogen synthesis) and that mutant-strain enzymes known to show less inhibition by physiological AMP levels also show less inhibition by physiological levels of GTP. This decreased inhibition by both AMP and GTP can almost totally account for the higher cellular rates of glycogen synthesis observed in the mutant strains. In addition, in metabolic conditions where we have shown that cellular glycogen synthesis increases, cellular GTP levels are known to decrease. Thus, we conclude that GTP inhibition is physiologically relevant.
D000249:Adenosine Monophosphate / Q000494:pharmacology; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology*; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors*; D006160:Guanosine Triphosphate / Q000502:physiology*; D007700:Kinetics; D012265:Ribonucleotides / Q000494:pharmacology; D013214:Starch Synthase / Q000037:antagonists & inhibitors*
D012265:Ribonucleotides; D000249:Adenosine Monophosphate; D006160:Guanosine Triphosphate; D005964:Glucosyltransferases; D013214:Starch Synthase