2,3-Cyclopyrophosphoglycerate in methanogens: evidence by 13C NMR spectroscopy for a role in carbohydrate metabolism.
The novel compound 2,3-cyclopyrophosphoglycerate (CPP) is the major small molecule carbon pool in Methanobacterium thermoautotrophicum. High-field 13C NMR 13CO2 pulse/unenriched CO2 chase experiments have shown that the labeled CPP rapidly loses its 13C to an insoluble pool, while the CPP steady-state concentration is maintained (as monitored by 31P NMR spectroscopy). The biosynthesis of CPP from CO2, acetyl coenzyme A, and pyruvate as precursors has been established by a 13C NMR study of ethanol extracts of Mb. thermoautotrophicum fed with 13CO2, [1-13C]- and [2-13C]acetate, and [1-13C]pyruvate. That CPP is a post-phosphoenolpyruvate metabolite has been confirmed by in vitro experiments with cell extracts. A role for CPP in carbohydrate metabolism was established when [1-13C]glucose fed to cells resulted in the formation of [3-13C]CPP exclusively. Possible functions of CPP within the cell are discussed.
D019794:2,3-Diphosphoglycerate; D050260:Carbohydrate Metabolism; D002247:Carbon Isotopes; D019605:Euryarchaeota / Q000201:enzymology* / Q000254:growth & development; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009943:Organophosphorus Compounds / Q000096:biosynthesis / Q000378:metabolism*
D002247:Carbon Isotopes; D009943:Organophosphorus Compounds; D019794:2,3-Diphosphoglycerate; C039905:cyclic-2,3-diphosphoglycerate