Your Ad Here
Loading

Pyruvic acid

Pyruvic acid
IUPAC name
Other names α-ketopropionic acid; acetylformic acid; pyroracemic acid; Pyr
Identifiers
CAS number 127-17-3 Yes check.svgY
SMILES
ChemSpider ID 1031
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) 2.49 at 25 °C
Related compounds
Other anions pyruvate ion
Pyruvat.svg   Pyruvate-3D-balls.png
Related keto-acids, carboxylic acids acetic acid
glyoxylic acid
oxalic acid
propionic acid
acetoacetic acid
Related compounds propionaldehyde
glyceraldehyde
methylglyoxal
sodium pyruvate
 Yes check.svgY (what is this?)  (verify)
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. It is also a ketone, as well as being the simplest alpha-keto acid. The carboxylate (COOH) ion (anion) of pyruvic acid, CH3COCOO-, is known as pyruvate, and is a key intersection in several metabolic pathways. It can be made from glucose through glycolysis, supplies energy to living cells in the citric acid cycle, and can also be converted to carbohydrates via gluconeogenesis, to fatty acids or energy through acetyl-CoA, to the amino acid alanine and to ethanol.

 Chemistry

Pyruvic acid is a colorless liquid with a smell similar to that of acetic acid. It is miscible with water, and soluble in ethanol and diethyl ether. In the laboratory, pyruvic acid may be prepared by heating a mixture of tartaric acid and potassium hydrogen sulfate, by the oxidation of propylene glycol by a strong oxidizer (eg. potassium permanganate or bleach), or by the hydrolysis of acetyl cyanide, formed by reaction of acetyl chloride with potassium cyanide:

CH3COCl + KCN → CH3COCN
CH3COCN → CH3COCOOH

 Biochemistry

Pyruvate is an important chemical compound in biochemistry. It is the output of the anaerobic metabolism of glucose known as glycolysis. One molecule of glucose breaks down into two molecules of pyruvate, 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; alternatively, 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 called the citric 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 anaerobic respiration 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.

Reference ranges for blood tests, comparing blood content of pyruvate (shown in violet near middle) with other constituents.

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.

 Pyruvate 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.

phosphoenolpyruvate pyruvate kinase pyruvate
Phosphoenolpyruvate wpmp.png   Pyruvate wpmp.png
ADP ATP
Biochem reaction arrow reversible YYYY horiz med.png
ADP ATP
 
  pyruvate kinase

Compound C00074 at KEGG Pathway Database. Enzyme 2.7.1.40 at KEGG Pathway Database. Compound C00022 at KEGG Pathway Database.

 Pyruvate decarboxylation to acetyl CoA

Pyruvate decarboxylation by the pyruvate dehydrogenase complex produces acetyl-CoA.

pyruvate pyruvate dehydrogenase complex acetyl-CoA
Pyruvate wpmp.png   Acetyl co-A wpmp.png
CoA + NAD+ CO2 + NADH + H+
Biochem reaction arrow foward YYNN horiz med.png
 
 

 Pyruvate carboxylation to oxaloacetate

Carboxylation by the pyruvate carboxylase produces oxaloacetate.

pyruvate pyruvate carboxylase oxaloacetate
Pyruvate wpmp.png   Oxaloacetate wpmp.png
ATP + CO2 ADP + Pi
Biochem reaction arrow foward YYNN horiz med.png
 
 

 Transamination by the alanine aminotransferase

pyruvate alanine transaminase alanine
Pyruvate wpmp.png   Alanine wpmp.png
glutamate α-ketoglutarate
Biochem reaction arrow reversible YYYY horiz med.png
glutamate α-ketoglutarate
 
 

 Reduction to lactate

Reduction by the lactate dehydrogenase produces lactate.

pyruvate lactate dehydrogenase lactate
Pyruvate wpmp.png   Lactic-acid-skeletal.svg
NADH NAD+
Biochem reaction arrow reversible YYYY horiz med.png
NADH NAD+
 
 

 Origin of life

Current evolutionary theory on the origin of life posits that the first organisms were anaerobic because the atmosphere of prebiotic Earth was, in theory, almost barren of oxygen. As such, requisite biochemical materials must have preceded life. In vitro, iron sulfide at sufficient pressure and temperature catalyzes the formation of pyruvate. Thus, argues Günter Wächtershäuser, the mixing of iron-rich crust with hydrothermal vent fluid is suspected of providing the fertile basis for the formation of life.

 References

  • Cody, G. D.; Boctor, N. Z.; Filley, T. R.; Hazen, R. M.; Scott, J. H.; Sharma, A.; Yoder, H. S.; Jr, (2000). "Primordial Carbonylated Iron-Sulfur Compounds and the Synthesis of Pyruvate". Science 289 (5483): 1337. doi:10.1126/science.289.5483.1337. PMID 10958777.  edit


 

The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Pyruvic acid" modified November 23, 2009 with previous authors listed in its history.