title: Carbohydrate fluxes into alginate biosynthesis in Azotobacter vinelandii NCIB 8789: NMR investigations of the triose pools.
abstract: The metabolite flux of carbohydrates through primary catabolism and into hexose resynthesis has been investigated for alginic acid biosynthesis in Azotobacter vinelandii. To do these studies, we fed the microorganism a variety of 13C-labeled glucose precursors, including [U-13C6]glucose. The incorporations of the precursors were determined by 1D 13C-NMR, 2D 13C-DQF-COSY, and inverse triple-quantum correlation experiments. The results clearly show that the entire catabolism of hexose is through the Entner-Doudoroff (E-D) pathway and that the triose pools are in equilibrium. Reentry into gluconeogenesis prior to alginate synthesis occurs totally from the glyceraldehyde 3-phosphate generated by the E-D pathway. The obligatory intermediacy of triose intermediates in alginate biosynthesis was proved. The experiments and results presented in this paper constitute a new method for distinguishing the E-D pathway from glycolysis in bacteria.
authors.affiliation: Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Texas at Austin, Texas 78712-1074, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Beale
authors.forename: J L
authors.initials: JL
authors.lastname: Foster
mesh_terms: D000464:Alginates / Q000737:chemistry / Q000378:metabolism*; D016948:Azotobacter vinelandii / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D006019:Glycolysis; D006601:Hexoses / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D014306:Trioses / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000464:Alginates; D002241:Carbohydrates; D006601:Hexoses; D014306:Trioses; D005947:Glucose