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Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a
ketone In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they ...
functional group. Pyruvate, the conjugate base, CH3COCOO, is a key intermediate in several
metabolic pathway In biochemistry Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, ...
s throughout the cell. Pyruvic acid can be made from
glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water ...
through
glycolysis Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO−, and a hydrogen ion, H+. The Thermodynamic free energy, free energy released in this process is used to form the high-energy molecules ATP (adenosine tri ...

glycolysis
, converted back to
carbohydrate is a disaccharide found in animal milk. It consists of a molecule of D-galactose and a molecule of D-glucose bonded by beta-1-4 glycosidic linkage. A carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) ato ...
s (such as glucose) via
gluconeogenesis Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carboh ...

gluconeogenesis
, or to
fatty acid fatty acids have perfectly straight chain structure. Unsaturated ones are typically bent, unless they have a trans configuration. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical co ...
s through a reaction with
acetyl-CoA Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidation, ox ...
. It can also be used to construct the amino acid
alanine Alanine (symbol Ala or A) is an α-amino acid Amino acids are organic compounds that contain amino (–NH2) and Carboxylic acid, carboxyl (–COOH) functional groups, along with a Substituent, side chain (R group) specific to each amino acid. ...
and can be converted into
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic chemical compound. It is a simple alcohol File:Alcohol general.svg, upright=0.8, The bond angle between a hydroxyl group (-OH) and a c ...
or
lactic acid Lactic acid is an organic acid. It has a molecular formula CH3CH(OH)COOH. It is white in the solid state and it is miscibility, miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial s ...
via
fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzyme Enzymes () are proteins that act as biological catalysts (biocatalysts). Catalysts accelerate chemical reactions. The mo ...
. Pyruvic acid supplies energy to cells through the
citric acid cycle The citric acid cycle (CAC) – also known as the TCA cycle (tricarboxylic acid cycle) or the Krebs cycle – is a series of chemical reactions used by all aerobic organisms to release stored energy through the redox, oxidation of acety ...

citric acid cycle
(also known as the Krebs cycle) when oxygen is present ( aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking (lactic acid fermentation, lactic acid).


Chemistry

In 1834, Théophile-Jules Pelouze distilled tartaric acid and isolated glutaric acid and another unknown organic acid. Jöns Jacob Berzelius characterized this other acid the following year and named pyruvic acid because it was distilled using heat. The correct molecular structure was deduced by the 1870s. 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, 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 metabolism of
glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water ...
known as
glycolysis Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO−, and a hydrogen ion, H+. The Thermodynamic free energy, free energy released in this process is used to form the high-energy molecules ATP (adenosine tri ...

glycolysis
. One molecule of
glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water ...
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-CoA, acetyl-coenzyme A, which is the main input for a series of reactions known as the citric acid cycle, Krebs cycle (also known as the citric acid cycle or tricarboxylic acid cycle). Pyruvate is also converted to oxaloacetate by an anaplerotic reactions, anaplerotic reaction, which replenishes Krebs cycle intermediates; also, the oxaloacetate is used for
gluconeogenesis Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carboh ...

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 The citric acid cycle (CAC) – also known as the TCA cycle (tricarboxylic acid cycle) or the Krebs cycle – is a series of chemical reactions used by all aerobic organisms to release stored energy through the redox, oxidation of acety ...

citric acid cycle
or tricarboxylic 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 anaerobe, anaerobically, creating lactate in animals and
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic chemical compound. It is a simple alcohol File:Alcohol general.svg, upright=0.8, The bond angle between a hydroxyl group (-OH) and a c ...
in plants and microorganisms (and carp). Pyruvate from glycolysis is converted by fermentation (biochemistry), fermentation to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH in lactate fermentation (biochemistry), fermentation, or to acetaldehyde (with the enzyme pyruvate decarboxylase) and then to
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic chemical compound. It is a simple alcohol File:Alcohol general.svg, upright=0.8, The bond angle between a hydroxyl group (-OH) and a c ...
in Ethanol fermentation, alcoholic fermentation. Pyruvate is a key intersection in the network of
metabolic pathway In biochemistry Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, ...
s. Pyruvate can be converted into
carbohydrate is a disaccharide found in animal milk. It consists of a molecule of D-galactose and a molecule of D-glucose bonded by beta-1-4 glycosidic linkage. A carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) ato ...
s via
gluconeogenesis Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carboh ...

gluconeogenesis
, to
fatty acid fatty acids have perfectly straight chain structure. Unsaturated ones are typically bent, unless they have a trans configuration. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical co ...
s or energy through
acetyl-CoA Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidation, ox ...
, to the amino acid
alanine Alanine (symbol Ala or A) is an α-amino acid Amino acids are organic compounds that contain amino (–NH2) and Carboxylic acid, carboxyl (–COOH) functional groups, along with a Substituent, side chain (R group) specific to each amino acid. ...
, and to
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic chemical compound. It is a simple alcohol File:Alcohol general.svg, upright=0.8, The bond angle between a hydroxyl group (-OH) and a c ...
. Therefore, it unites several key metabolic processes.


Pyruvic acid production by glycolysis

In
glycolysis Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO−, and a hydrogen ion, H+. The Thermodynamic free energy, free energy released in this process is used to form the high-energy molecules ATP (adenosine tri ...

glycolysis
, phosphoenolpyruvic acid, phosphoenolpyruvate (PEP) is converted to pyruvate by pyruvate kinase. This reaction is strongly exergonic and irreversible; in
gluconeogenesis Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is the most abundant monosaccharide, a subcategory of carboh ...

gluconeogenesis
, it takes two enzymes, pyruvate carboxylase and PEP carboxykinase, to catalyze the reverse transformation of pyruvate to PEP.


Decarboxylation to acetyl CoA

Pyruvate decarboxylation by the pyruvate dehydrogenase complex produces
acetyl-CoA Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidation, ox ...
.


Carboxylation to oxaloacetate

Carboxylation by pyruvate carboxylase produces oxaloacetic acid, oxaloacetate.


Transamination to alanine

Transamination by alanine transaminase produces
alanine Alanine (symbol Ala or A) is an α-amino acid Amino acids are organic compounds that contain amino (–NH2) and Carboxylic acid, carboxyl (–COOH) functional groups, along with a Substituent, side chain (R group) specific to each amino acid. ...
.


Reduction to lactate

Reduction by lactate dehydrogenase produces lactate.


Uses

Pyruvate is sold as a Anti-obesity medication, weight-loss supplement, though credible science has yet to back this claim. A Clinical research, systematic review of six Clinical trial, trials found a statistically significant difference in body weight with pyruvate compared to placebo. However, all of the trials had methodological weaknesses and the magnitude of the effect was small. The review also identified Adverse effect, adverse events associated with pyruvate such as diarrhea, bloating, gas, and increase in low-density lipoprotein (LDL) cholesterol. The authors concluded that there was insufficient evidence to support the use of pyruvate for weight loss. There is also ''in vitro'' as well as ''in vivo'' evidence in hearts that pyruvate improves metabolism by NADH production stimulation and increases cardiac function.


See also

* Pyruvate scale


Notes


References

*


External links


Pyruvic acid mass spectrum
{{DEFAULTSORT:Pyruvic Acid Alpha-keto acids Cellular respiration Exercise physiology Metabolism