Phosphoenolpyruvate
2865295
187006595
2008-01-26T11:11:33Z
FragBait0
3260971
{{Chembox new
|ImageFile=Phosphoenolpyruvic acid.svg
|ImageSize=
|IUPACName=2-phosphonooxyprop-2-enoic acid
|OtherNames=Phosphoenolpyruvic acid, PEP
|Section1= {{Chembox Identifiers
| CASNo=138-08-9
| PubChem=1005
| SMILES=C=C(C(=O)O)OP(=O)(O)O
}}
|Section2= {{Chembox Properties
| Formula=C<sub>3</sub>H<sub>5</sub>O<sub>6</sub>P
| MolarMass=168.042
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
|Section3= {{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}
'''Phosphoenolpyruvate''' (synonyms: '''phosphoenolpyruvic acid''', '''PEP''') is an important [[chemical compound]] in [[biochemistry]]. It has the highest energy phosphate bond found (-61.9 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 [[Cell (biology)|cell]]s.
{{Biochemical Reaction
|reaction_A_major_substrate=[[2-phosphoglycerate|2-phospho-<small>D</small>-glycerate]]
|reaction_A_major_substrate_image=2-phospho-D-glycerate_wpmp.png
|reaction_A_foward_enzyme=[[Enolase]]
|reaction_A_reverse_enzyme=[[Enolase]]
|reaction_A_reaction_direction_(forward/reversible/reverse)=reversible
|reaction_A_minor_reverse_product(s)=
|reaction_A_minor_reverse_substrate(s)=H<sub>2</sub>O
|reaction_A_minor_foward_substrate(s)=
|reaction_A_minor_foward_product(s)=H<sub>2</sub>O
|reaction_A_major_product=[[phosphoenolpyruvate]]
|reaction_A_major_product_image=phosphoenolpyruvate_wpmp.png
|reaction_B_foward_enzyme=[[Pyruvate kinase]]
|reaction_B_reverse_enzyme=[[Pyruvate kinase]]
|reaction_B_reaction_direction_(foward/reversible/reverse)=reversible
|reaction_B_minor_foward_substrate(s)=[[ADP]]
|reaction_B_minor_foward_product(s)=[[adenosine triphosphate|ATP]]
|reaction_B_minor_reverse_product(s)=
|reaction_B_minor_reverse_substrate(s)=
|reaction_B_major_product=[[pyruvate]]
|reaction_B_major_product_image=pyruvate_wpmp.png
}}
{{KEGG compound|C00631}} {{KEGG enzyme|4.2.1.11}} {{KEGG compound|C00074}} {{KEGG enzyme|2.7.1.40}} {{KEGG compound|C00022}}
==In gluconeogenesis==
PEP is formed from the [[decarboxylation]] of [[oxaloacetate]] and [[hydrolysis]] of one [[guanosine triphosphate]] molecule. This reaction is [[catalysis|catalyzed]] by the enzyme [[phosphoenolpyruvate carboxykinase]] (PEPCK). This reaction is a [[rate-limiting]] step in gluconeogenesis:<ref>{{cite web |url=http://www.ebi.ac.uk/interpro/IEntry?ac=IPR008209 |title=InterPro: IPR008209 Phosphoenolpyruvate carboxykinase, GTP-utilising |accessdate=2007-08-17 |format= |work=}}</ref>
:'''GTP + oxaloacetate → GDP + phosphoenolpyruvate + CO<sub>2</sub>'''
==In plants==
PEP may be used for the synthesis of [[chorismate]] through the [[shikimate]] pathway.<ref>{{cite web |url=http://www.biocarta.com/pathfiles/chorismatePathway.asp |title=BioCarta - Charting Pathways of Life |accessdate=2007-08-17 |format= |work=}}</ref> Chorismate may then be metabolized into the aromatic [[amino acid]]s ([[phenylalanine]], [[tryptophan]] and [[tyrosine]]) and other aromatic compounds.
In addition, in [[C₄ carbon fixation|C₄ plants]], PEP serves as an important [[Substrate (biochemistry)|substrate]] in [[carbon fixation]]. The chemical equation, as catalyzed by [[phosphoenolpyruvate carboxylase]] (PEP carboxylase), is:
:'''PEP + CO<sub>2</sub> → oxaloacetate'''
==References==
<references/>
{{glycolysis}}
[[Category:Carboxylic acids]]
[[Category:Glycolysis]]
[[Category:Organophosphates]]
[[de:Phosphoenolbrenztraubensäure]]
[[it:Fosfoenolpiruvato]]
[[fr:Phosphoénol pyruvate]]
[[ja:ホスホエノールピルビン酸]]
[[zh:磷酸烯醇丙酮酸]]