Figure 3.

Transfer of ¹³C-label from [1,2-¹³C₂]glucose into alanine of Fth Beaver (1), Fth LVS (2), or Fno (3). (A) ¹³C-Excess (mol%) and the fractional isotopolog distributions (%) in the silylated fragments Ala-260 and Ala-232 carrying C1-C3 and C2-C3 of the original alanine carbon chain, respectively. (B) Conversion of [1,2-¹³C₂]glucose into pyruvate and alanine via glycolysis (EMP) (left, with red bars indicating the ¹³C-labels) or the Entner-Doudoroff pathway (ED) (right, with green bars indicating the ¹³C-labels). The observed label distribution with ¹³C at C2 and C3 (indicated by red bars in panel A), only matches the predicted pattern via the EMP in panel (B). For more details, see also text.