Phosphoenol Pyruvate (PEP)

PEP is a high energy intermediate of glycolysis, gluconeogenesis, and the C 4 plant cycle for concentrating CO 2. The high energy phosphate of PEP contains sufficient for substrate level phosphorylation of ADP to form ATP and pyruvate, as shown below:

> Phosphoenolpyruvate + ADP + H+ <=> Pyruvate + ATP (catalyzed by Pyruvate Kinase)

PEP functions in the PEP-dependent phosphotransferase system (PTS) of E. coli , which transports and phosphorylates sugars. PEP is used in synthesis of N-acetylneuraminic acid 9-phosphate (Figure 16.14)

Enzymes that act on PEP include PEPCK, enolase, pyruvate kinase, pyruvate-phosphate dikinase, PEP Carboxylase, and 5-enoylpyruvaylshikimate-3-phosphate synthase (EPSP synthase)

See also: Glycolysis, Gluconeogenesis, The C 4 Cycle (from Chapter 17), Glycolysis Reaction Summaries, PEPCK, Enolase, Pyruvate Kinase

INTERNET LINK: Glycolysis/Gluconeogenesis