Phosphoenolpyruvate

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Template:Chembox E number
Phosphoenolpyruvate
IUPAC name 2-phosphonooxyprop-2-enoic acid
Other names Phosphoenolpyruvic acid, PEP
Identifiers
3D model (JSmol)
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Properties
C3H5O6P
Molar mass 168.042
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Phosphoenolpyruvate (synonyms: phosphoenolpyruvic acid, PEP) is an important chemical compound in biochemistry. It has the highest energy phosphate bond found (-62 KJ/mol) in living organisms, and is involved in glycolysis and gluconeogenesis. In plants, it is also involved in the biosynthesis of various aromatic compounds, and in carbon fixation.

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
2-phospho-D-glycerate wpmp.png   Phosphoenolpyruvate wpmp.png   Pyruvate wpmp.png
H2O ADP ATP
Biochem reaction arrow reversible NYYN horiz med.png 75px
H2O
   
  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.

In gluconeogenesis

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

GTP + oxaloacetate → GDP + phosphoenolpyruvate + CO2

In plants

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

References

  1. "InterPro: IPR008209 Phosphoenolpyruvate carboxykinase, GTP-utilising". Retrieved 2007-08-17.
  2. "BioCarta - Charting Pathways of Life". Retrieved 2007-08-17.


de:Phosphoenolbrenztraubensäure it:Fosfoenolpiruvato


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