Figure 3.

Deconvolution of carbon fluxes contributing to UDP-Glc, UDP-GlcNAc, and CMP-Neu5Ac synthesis. (a) Schematic representation of the structures of the nucleotide sugars and products of their fragmentation, including positions of labels derived from different metabolic precursors. Fragmentation of the nucleotide sugar molecule along the phosphodiester bond allows for independent detection of labeled variants of the sugar moiety (neutral loss) and the nucleotide moiety (product ion) as shown for three nucleotide sugars in this figure (and for the other nucleotide sugars of interest in Supplementary Figure S2). (b,c) Time courses of isotopologues separated only based on their precursor mass (b), and after label deconvolution based on MS/MS data (c).