Physiologic interactions between L-proline and D-glucose in Leishmania tarentolae, L. donovani and Trypanosoma scelopori culture forms.

L-proline is more completely catabolized by Leishmania tarentolae and Trypanosoma scelopori than by L. donovani. In the two former organisms the activity of 14CO2 derived from L-proline-14C was as high or higher than that derived from D-glucose-14C; in L. donovani more 14CO2 is derived from D-glucose-14C than from L-proline-14C. Addition of unlabeled D-glucose to cells incubated with L-proline-14C resulted in increased 14C-activity of TCA-soluble fractions of L. tarentolae and T. scelopori; 14C-activity of 5% TCA insoluble fractions of these cells remained unchanged. Some of the increased 14C-label found in the soluble fraction was in glutamate and aspartate. This increased activity in glutamate and aspartate was accompanied by a decrease in alanine-14C in the free amino acid pool. These results suggest that there are complex physiological interactions between glucose and proline in the metabolism of L. tarentolae, L. donovani and T. scelopori. In addition, proline appears to have a more central role in the amino acid metabolism of L. tarentolae and T. scelopori whereas glucose may be more significant in L. donovani.