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]]