Extended Data Fig. 3: [1,2-13C2]- and [5,6-13C2]-glucose reveal fluxes through different glycolytic routes.
From: A parallel glycolysis provides a selective advantage through rapid growth acceleration
a, [1,2-13C2]-glucose uniquely generates M + 1 labeled triose phosphates through the oxidative pentose phosphate pathway (OxPPP). For every three glucose molecules going through the PPP, three molecules of M + 0, one molecule of M + 1, and one molecule of M + 2 triose phosphate are generated. b, [5,6-13C2]-glucose introduces unlabeled lower glycolytic intermediates only through the EMP pathway. Unlike in the case of [1,2-13C2]-glucose, the EMP and the ED pathways produce the same positionally labeled pyruvate. The major fraction of M + 2 3PG indicated the ED pathway activity in the nutrient replete condition. c, Using the carbon balance model of central carbon metabolism with [5,6-13C2]-glucose, 3PG and pyruvate (PYR) labeling measurements are sufficient to solve for central carbon metabolism fluxes. This elegant solution is attributable to the fact that [5,6-13C2]-glucose tracing is not convoluted by carbon shuffling in the PPP. Mass balance of carbons over the EMP pathway, the ED pathway, and the PPP (the inner control volume) as well as lower glycolysis (the outer control volumes) revealed the relationship between 3PG and PYR labeling and the central carbon metabolism fluxes.
