FIGURE 3.

[2,3-¹⁴C]fumarate incorporation into nucleic acids and proteins by parasitized erythrocytes and free parasites. A, structure and radio-TLC analysis of [2,3-¹⁴C]fumarate (10 mCi mmol⁻¹) in which the second and third carbon atoms are enriched in ¹⁴C. B, [2,3-¹⁴C]fumarate incorporation by parasitized erythrocytes after incubation with the radioactive label for 24 and 48 h. 1 μCi of [2,3-¹⁴C]fumarate was added to PRBCs and RBCs, and cells were harvested and counted for radioactivity as described under “Experimental Procedures.” C, parasitized erythrocytes incubated with 1 μCi of [2,3-¹⁴C]fumarate for 24 h were treated with 0.15% saponin solution to release free parasites from erythrocytes. The parasite pellet was washed, processed, and subjected to SDS-PAGE, which was stained by Coomassie Brilliant Blue (i) and developed using a Fuji FLA-5000 phosphorimaging device (ii). D, radioactive incorporation in the nucleic acid fractions of saponin released erythrocyte-free parasites incubated with varying amounts of [2,3-¹⁴C]fumarate.