title: A new synthesis of adenosine 5'-([gamma(R)-17O,18O]-gamma-thiotriphosphate) and its use to determine the stereochemical course of the activation of glutamate by glutamine synthetase.
abstract: A new synthetic route to adenosine 5'-([gamma(R)-17O,18O]-gamma-thiotriphosphate) is described which combines chemical methods for introducing the heavy oxygen isotopes and enzymic methods for achieving the enantiospecificity. This material was used as a substrate for the activation of glutamate catalyzed by glutamine synthetase from Salmonella typhimurium. Analysis of the chirality of the [16O,17O,18O]thiophosphate produced showed that the reaction proceeds with inversion of configuration on phosphorus. This result, taken together with the positional isotope exchange studies of Midelfort and Rose [Midelfort, C. F., & Rose, I.A. (1976) J. Biol. Chem. 251, 5881-5887], demonstrates that the activation of glutamate to form gamma-glutamyl phosphate proceeds by a direct "in-line" transfer of the phosphoryl group.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D007202:Indicators and Reagents; D007553:Isotope Labeling / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010103:Oxygen Isotopes; D012486:Salmonella typhimurium / Q000201:enzymology
chemical_list: D005971:Glutamates; D007202:Indicators and Reagents; D010103:Oxygen Isotopes; C022571:adenosine 5'-O-(3-thiotriphosphate); D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D005974:Glutamate-Ammonia Ligase