Figure 2.

¹H-NMR analysis of excreted end-products from glucose and threonine metabolism. Metabolic end-products (succinate, pyruvate, and acetate) excreted by the procyclic wild-type cell line (A and B), the Δpdh mutant (D) and the tetracycline-induced ^RNAiTDH.i (C), ^RNAiTDH/^RNAiPDH.i (E) and Δach/^RNAiASCT.i (F) mutants from d-[U-¹³C]-glucose and/or threonine was determined by ¹H-NMR. The cells were incubated in PBS containing 4 mM d-[U-¹³C]-glucose with (_GT) or without (_G) 4 mM threonine. Each spectrum corresponds to one representative experiment from a set of at least 3. A part of each spectrum ranging from 1.6 ppm to 2.6 ppm is shown (see panels A and C). The resonances were assigned as indicated in panels B and F: A₁₂, acetate; A₁₃, ¹³C-enriched acetate; P₁₂, pyruvate; P₁₃, ¹³C-enriched pyruvate; S₁₂, succinate; S₁₃, ¹³C-enriched succinate.