Description
Phosphoenolpyruvic acid plays a role in both glycolysis and gluconeogenesis. During glycolysis, it is formed by the action of enolase on 2-phosphoglycerate and is metabolized to pyruvate by pyruvate kinase. One molecule of ATP is formed during its metabolism in this pathway. During gluconeogenesis, it is formed from phosphoenolpyruvate carboxykinase-catalyzed oxaloacetate decarboxylation and GTP hydrolysis. In plants, it is metabolized to form aromatic amino acids and also serves as a substrate for phosphoenolpyruvate carboxylase-catalyzed carbon fixation.
Chemical Properties
white to light yellow fine crystalline powder
Uses
Substrate for many kinase reactions.
Uses
Phosphoenolpyruvic acid monopotassium salt is used in glycolysis and gluconeogeneis. It is used for regeneration of ATP from ADP in enzyme-catalyzed syntheses. It is metabolized by an enzyme namely pyruvate kinase to yield pyruvate. It acts as protection against cell injury induced by oxidative stress and against dysfunction in carbohydrate metabolism.
General Description
Phospho(enol)pyruvic acid (PEP) acts as an inhibitor of hexokinase, phosphoglucose isomerase, phosphofructokinase and aldolase. It is a bifunctional carbohydrate, which exhibits antioxidant property. PEP may be a potential organ preservation agent in clinical transplantation.
Biochem/physiol Actions
Phospho(enol)pyruvic acid (PEP) is involved in glycolysis and gluconeogeneis. In glycolysis, PEP is metabolized by Pyruvate Kinase to yield pyruvate. In plants, PEP is involved in the formation of aromatic amino acids as well as in the carbon fixation pathway.
Purification Methods
KPEP is purified via the monocyclohexylamine salt (see next entry). The salt (534mg) in H2O (10mL) is added to Dowex 50Wx4 H+ form (200-400 mesh, 2mL, H2O washed) and stirred gently for 30minutes and filtered. The resin is washed with H2O (6mL), and the combined solutions are adjusted to pH 7.4 with 3N KOH (~1.4mL) and the volume adjusted to 18.4mL with H2O to give a solution of 0.1M KPEP which can be lyophilised to a pure powder and is very good for enzyme work. It has been recrystallised from MeOH/Et2O. [Clark & Kirby Biochemical Preparations 11 103 1966, Wold & Ballou J Biol Chem 227 301 1957, Cherbuliez & Rabinowitz Helv Chim Acta 39 1461 1956, Beilstein 3 IV 977.] The triNa salt [5541-93-5] M 360.0, is purified as follows: the salt (1g) is dissolved in MeOH (40mL) and dry Et2O is added in excess. The white crystals are collected and dried over P2O5 at 20o. [Cramer & Voges Chem Ber 92 952 1959, Beilstein 3 IV 977.]
