Pyruvate

Pyruvate

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Pyruvic acid

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Identifiers
CAS number 127-17-3 YesY
PubChem 1060
ChemSpider 1031 YesY
UNII 8558G7RUTR YesY
DrugBank DB00119
KEGG C00022 YesY
ChEBI CHEBI:32816 YesY
Jmol-3D images Image 1
Properties
Molecular formula C3H4O3
Molar mass 88.06 g/mol
Density 1.250 g/cm³
Melting point

11.8 °C, 285 K, 53 °F

Boiling point

165 °C, 438 K, 329 °F

Acidity (pKa) 2.50[1]
Related compounds
Other anions pyruvate ion
Related keto-acids, carboxylic acids acetic acid
glyoxylic acid
oxalic acid
propionic acid
acetoacetic acid
Related compounds propionaldehyde
glyceraldehyde
methylglyoxal
sodium pyruvate
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Pyruvic acid (CH3COCOOH) is an organic acid, a ketone, as well as the simplest of the alpha-keto acids. The carboxylate (COO) anion of pyruvic acid, its Brønsted–Lowry conjugate base, CH3COCOO, is known as pyruvate, and is a key intersection in several metabolic pathways.

Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through acetyl-CoA. It can also be used to construct the amino acid alanine and be converted into ethanol.

Pyruvic acid supplies energy to living cells through the citric acid cycle (also known as the Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactic acid when oxygen is lacking (fermentation).

Chemistry

In 1834, Théophile-Jules Pelouze distilled both tartaric acid (L-tartaric acid) and racemic acid (a mix of D- and L-tartaric acid) and isolated pyrotartaric acid (methyl succinic acid[2]) and another acid that Jöns Jacob Berzelius characterized the following year and named pyruvic acid.[3] Pyruvic acid is a colorless liquid with a smell similar to that of acetic acid and is miscible with water. In the laboratory, pyruvic acid may be prepared by heating a mixture of tartaric acid and potassium hydrogen sulfate,[4] by the oxidation of propylene glycol by a strong oxidizer (e.g., potassium permanganate or bleach), or by the hydrolysis of acetyl cyanide, formed by reaction of acetyl chloride with potassium cyanide:

CH3COCl + KCN → CH3COCN + KCl
CH3COCN → CH3COCOOH

Biochemistry

Pyruvate is an important chemical compound in biochemistry. It is the output of the anaerobic metabolism of glucose known as glycolysis.[5] One molecule of glucose breaks down into two molecules of pyruvate,[5] which are then used to provide further energy, in one of two ways. Pyruvate is converted into acetyl-coenzyme A, which is the main input for a series of reactions known as the Krebs cycle. Pyruvate is also converted to oxaloacetate by an anaplerotic reaction, which replenishes Krebs cycle intermediates; also, the oxaloacetate is used for gluconeogenesis. These reactions are named after Hans Adolf Krebs, the biochemist awarded the 1953 Nobel Prize for physiology, jointly with Fritz Lipmann, for research into metabolic processes. The cycle is also known as the citric acid cycle or tri-carboxylic acid cycle, because citric acid is one of the intermediate compounds formed during the reactions.

If insufficient oxygen is available, the acid is broken down anaerobically, creating lactate in animals and ethanol in plants and microorganisms. Pyruvate from glycolysis is converted by fermentation to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH in lactate fermentation, or to acetaldehyde and then to ethanol in alcoholic fermentation.

Pyruvate is a key intersection in the network of metabolic pathways. Pyruvate can be converted into carbohydrates via gluconeogenesis, to fatty acids or energy through acetyl-CoA, to the amino acid alanine, and to ethanol. Therefore, it unites several key metabolic processes.


The pyruvic acid derivative bromopyruvic acid is being studied for potential cancer treatment applications by researchers at Johns Hopkins University in ways that would support the Warburg hypothesis on the cause(s) of cancer.

Pyruvic acid production by glycolysis

In glycolysis, phosphoenolpyruvate (PEP) is converted to pyruvate by pyruvate kinase. This reaction is strongly exergonic and irreversible; in gluconeogenesis, it takes two enzymes, pyruvate carboxylase and PEP carboxykinase, to catalyze the reverse transformation of pyruvate to PEP. Template:Enzymatic Reaction Compound KEGG Pathway Database.

Template:GlycolysisGluconeogenesis WP534

Decarboxylation to acetyl CoA

Pyruvate decarboxylation by the pyruvate dehydrogenase complex produces acetyl-CoA. Template:Enzymatic Reaction

Carboxylation to oxaloacetate

Carboxylation by pyruvate carboxylase produces oxaloacetate. Template:Enzymatic Reaction

Transamination to alanine

Transamination by alanine transaminase produces alanine. Template:Enzymatic Reaction

Reduction to lactate

Reduction by lactate dehydrogenase produces lactate. Template:Enzymatic Reaction

See also

Notes

References