Phosphoenolpyruvate

Phosphoenolpyruvate
Image:Phosphoenolpyruvic acid.svg
Chemical name	2-phosphonooxyprop-2-enoic acid
Other names	Phosphoenolpyruvic acid, PEP
Chemical formula	C₃H₅O₆P
SMILES	C=C(C(=O)O)OP(=O)(O)O
Molecular mass	168.042 g/mol
Melting point	? °C
CAS number	[138-08-9]
Disclaimer and references

Phosphoenolpyruvate (synonyms: Phosphoenolpyruvic acid, PEP) is an important chemical compound in biochemistry. It has a high energy phosphate bond, and is involved in glycolysis and gluconeogenesis. In plants, it is also involved in the biosynthesis of various aromatic compounds, and in carbon fixation.

[edit] In glycolysis

PEP is formed by the action of the enzyme enolase on 2-phosphoglycerate. Metabolism of PEP to pyruvate by pyruvate kinase (PK) generates 1 molecule of adenosine triphosphate (ATP) via substrate-level phosphorylation. ATP is one of the major currencies of chemical energy within cells.

2-phospho-D-glycerate	Enolase		phosphoenolpyruvate	Pyruvate kinase		pyruvate
Image:2-phospho-D-glycerate wpmp.png			Image:Phosphoenolpyruvate wpmp.png			Image:Pyruvate wpmp.png
		H₂O		ADP	ATP
	Image:Biochem reaction arrow reversible NYYN horiz med.png			Image:Biochem reaction arrow reversible YYYY horiz med.png
		H₂O		ADP	ATP

	Enolase			Pyruvate kinase

Compound C00631 at KEGG Pathway Database. Enzyme 4.2.1.11 at KEGG Pathway Database. Compound C00074 at KEGG Pathway Database. Enzyme 2.7.1.40 at KEGG Pathway Database. Compound C00022 at KEGG Pathway Database.

PEP is formed from the decarboxylation of oxaloacetate and hydrolysis of 1 guanosine triphosphate molecule. This reaction is catalyzed by the enzyme phosphoenolpyruvate carboxykinase (PEPCK). This reaction is a rate-limiting step in gluconeogenesis, and is [1]:

GTP + oxaloacetate → GDP + phosphoenolpyruvate + CO2

PEP may be used for the synthesis of chorismate through the shikimate pathway [2]. Chorismate may then be metabolized into the aromatic amino acids (phenylalanine, tryptophan and tyrosine) and other aromatic compounds.

Additionally, in C₄ plants, PEP serves as an important substrate in carbon fixation. The chemical equation, as catalyzed by phosphoenolpyruvate carboxylase (PEP carboxylase), is:

PEP + CO2 → oxaloacetate

Image:Glucose wpmp.png	This metabolism related chemical article is a stub. You can help Wikipedia by expanding it.
	This article is of interest to the Metabolic Pathways WikiProject.