Reaction ID Reaction Direction allowed rxn10122 NADH dehydrogenase (ubiquinone-8 3.5 protons) Backwards only rxn08971 NADH dehydrogenase (menaquinone-8 0 protons) Forwards only rxn08975 NADH dehydrogenase (ubiquinone-8 ) Forwards only rxn08976 NADH dehydrogenase (demethylmenaquinone-8 0 protons) Forwards only rcure021 succinate:ubiquinone oxidoreductase Forwards only rxn08527 fumarate reductase Forwards only rxn08528 fumarate reductase Forwards only rxn08558 glycerol-3-phosphate dehydrogenase (demethylmenaquinone-8) Forwards only rxn08655 Glycolate oxidase Forwards only rxn08783 D-lactate dehydrogenase Forwards only rxn08792 L-Lactate dehydrogenase (ubiquinone) Forwards only rxn09272 succinate dehydrogenase Forwards only rxn12500 tricarballylate dehydrogenase Forwards only