FIGURE 5.

Metabolic intermediates in fumarate metabolism. A, pathways for fumarate metabolism. Fumarate can be converted to aspartate through the metabolic intermediates malate and oxaloacetate, or fumarate can be directly acted upon by aspartase to generate aspartate. B and C, RBCs (B) and PRBCs (C) incubated with 10 mm [2,3-¹³C]fumarate in 1× PBS at 37 °C for 4 h. Cell suspension was lysed and processed as described under “Experimental Procedures.” D₂O was added to a final concentration of 10% as an internal lock to the cell lysate, and NMR spectra were recorded.