EXPRESS: Balanced overall equation for the complete oxidation of glucose: resolving a 30-year stoichiometric controversy
Yumiko Motoyama, Kei Wada, Nobuhiro YukawaDoes glucose oxidation yield 6 or 10 H 2 O? Debated 30 years ago and revived in 2025, the question underlies a brain metabolic water budget built on C 6 H 1 2 O 6 + 6O 2 → 6CO 2 + 10H 2 O, which does not satisfy the law of conservation of mass. The balanced form, C 6 H 1 2 O 6 + 6O 2 + 4ADP 3 ⁻ + 4HPO 4 2 ⁻ + 4H⁺ → 6CO 2 + 10H 2 O + 4ATP 4 ⁻, combines combustion (6H 2 O) with substrate-level phosphorylation (4H 2 O). This reconciles both answers, resolving the controversy. How much water is secreted per glucose depends on the fate of ATP; choosing 6 or 10 changes estimates of brain metabolic water by two-thirds.