title: 31P nuclear magnetic resonance studies of the fermentation of glucose to ethanol by Zymomonas mobilis.
abstract: High resolution 31P nuclear magnetic resonance spectroscopy has been employed to study the fermentation of glucose to ethanol by Zymomonas mobilis, strain ZM4, a bacterium which uses the Entner-Doudoroff pathway. The levels of nucleoside triphosphates, sugar phosphates, UDP-sugars and Pi in intact fermenting cells have been studied with a time resolution of 1 min. It is suggested that a pH gradient is established across the cell membrane during fermentation and that the intracellular pH does not rise above approximately 6.4. 31P resonances from most phosphorus-containing intermediates in the Entner-Doudoroff pathway, as well as adenosine and uridine nucleotides and a number of other intracellular metabolites, have been assigned in perchloric extracts of fermenting cells by means of a number of techniques, including two-dimensional homonuclear J-resolved and two-dimensional homonuclear shift-correlated spectroscopy. Quantification of these metabolites in spectra of extracts of fermenting cells indicates that the rate-limiting steps in the Entner-Doudoroff pathway in Z. mobilis are the conversions of glucose 6-phosphate to 6-phosphogluconate and of 3-phosphoglycerate to 2-phosphoglycerate.
mesh_terms: D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy
chemical_list: D000431:Ethanol; D005947:Glucose