Sequence of a Giardia lamblia gene coding for the glycolytic enzyme, pyruvate,phosphate dikinase

Contribution of Pyruvate Phosphate Dikinase in the Maintenance of the Glycosomal ATP/ADP Balance in the Trypanosoma brucei Procyclic Form

“…In C4 plants, PPDK operates in the gluconeogenic direction (production of P-enolpyruvate from pyruvate) and contributes to CO 2 fixation through photosynthesis. Involvement of PPDK in glycolysis (production of pyruvate from P-enolpyruvate) has been suggested in a number of eukaryotes, including Phytophthora (1), Giardia (2,3), Entamoeba (4), and Trypanosoma (5-7), however, its coexistence with the ATP-dependent glycolytic pyruvate kinase (EC 2.7.1.40) makes it difficult to address its role. Here we address this question in Trypanosoma brucei, using very powerful reverse genetic approaches developed in this eukaryotic model.…”

“…1A). Most of the glycolysis takes place in specialized peroxisomes, called glycosomes (steps [1][2][3][4][5][6] (17). In the course of glycolysis, P-enolpyruvate is produced in the cytosol (steps 10 -12), where it is located at a branching point.…”

Reconstructing the Mosaic Glycolytic Pathway of the Anaerobic Eukaryote Monocercomonoides

“…However, pyrophosphate-fructose-6-phosphate phosphotransferase (PFP) or inorganic pyrophosphate (PPi)-dependent PFK performs the same task using PPi as the phosphate donor; this reaction is reversible due to a much lower G° ( 25). Similarly, in the final step of the glycolytic pathway, several enzymes exist that catalyze the conversion of phosphoenolpyruvate to pyruvate (26). The reaction catalyzed by PK, the enzyme found in most eukaryotes and prokaryotes (26), is irreversible due to its high free energy demand.…”

“…Similarly, in the final step of the glycolytic pathway, several enzymes exist that catalyze the conversion of phosphoenolpyruvate to pyruvate (26). The reaction catalyzed by PK, the enzyme found in most eukaryotes and prokaryotes (26), is irreversible due to its high free energy demand. However, pyruvate phosphate dikinase (PPDK) is the energy-conserving, reversible alternative to PK (26,34).…”

“…The reaction catalyzed by PK, the enzyme found in most eukaryotes and prokaryotes (26), is irreversible due to its high free energy demand. However, pyruvate phosphate dikinase (PPDK) is the energy-conserving, reversible alternative to PK (26,34). Since both PFP and PPDK rely on PPi as the phosphate donor, they can thus increase the overall ATP yield of glycolysis by using a byproduct of the cell's anabolic processes as an energy source rather than hydrolyzing ATP.…”