(PEP) An important phosphorylated intermediate of glucose metabolism. In glycolysis PEP is the immediate precursor of pyruvic acid, while in the synthesis of glucose from acetyl-CoA, PEP is formed from oxaloacetate generated in the *glyoxylate cycle
. In C4
plants PEP is an intermediate in the Hatch-Slack pathway. The aromatic amino acids, and hence a large number of other aromatic nitrogenous compounds, are also synthesized from PEP.