Pyruvic acid
81666
225606369
2008-07-14T15:01:28Z
164.111.191.107
Minor revision to introduction paragraph - rearrangement of sentences
{{Chembox new
| Name = Pyruvic acid
| ImageFileL1 = Pyruvic-acid-2D-skeletal.png
| ImageSizeL1 = 120px
| ImageFileR1 = Pyruvic-acid-3D-balls.png
| ImageSizeR1 = 120px
| IUPACName = 2-oxopropanoic acid
| OtherNames = α-ketopropionic acid; acetylformic acid; pyroracemic acid; Pyr
| Section1 = {{Chembox Identifiers
| CASNo = 127-17-3
| SMILES = CC(C(O)=O)=O
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>3</sub>H<sub>4</sub>O<sub>3</sub>
| MolarMass = 88.06 g/mol
| Density = 1.250 g/cm³
| MeltingPt = 11.8 °C
| BoilingPt = 165 °C
}}
}}
'''Pyruvic acid''' (CH<sub>3</sub>COCO<sub>2</sub>H) is an [[keto acids|alpha-keto acid]]. The [[carboxylate]] [[anion]] of pyruvic acid is known as '''pyruvate'''. Pyruvate plays an important role in biochemical processes.
==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]]:
:CH<sub>3</sub>COCl + KCN → CH<sub>3</sub>COCN
:CH<sub>3</sub>COCN → CH<sub>3</sub>COCOOH
==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-CoA|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 reactions|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 [[anaerobe|anaerobically]], creating [[lactate]] in animals and [[ethanol]] in plants. Pyruvate from glycolysis is converted by [[anaerobic respiration]] to [[lactic acid|lactate]] using the [[enzyme]] [[lactate dehydrogenase]] and the [[coenzyme]] [[NADH]] in lactate [[fermentation (biochemistry)|fermentation]], or to [[acetaldehyde]] and then to ethanol in alcoholic fermentation.
Pyruvate is a key intersection in the network of [[metabolic pathway]]s. Pyruvate can be converted to [[carbohydrate]]s via [[gluconeogenesis]], to [[fatty acid]]s 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.
===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. The arrow indicating a reverse reaction in the Figure below is incorrect.
{{Enzymatic Reaction
|foward_enzyme=[[Pyruvate kinase]]
|reverse_enzyme=[[Pyruvate kinase]]
|substrate=[[phosphoenolpyruvate]]
|product=pyruvate
|reaction_direction_(foward/reversible/reverse)=reversible
|minor_foward_substrate(s)=[[ADP]]
|minor_foward_product(s)=[[adenosine triphosphate|ATP]]
|minor_reverse_substrate(s)=[[adenosine triphosphate|ATP]]
|minor_reverse_product(s)=[[ADP]]
|substrate_image=phosphoenolpyruvate_wpmp.png
|product_image=pyruvate_wpmp.png
}}
{{KEGG compound|C00074}} {{KEGG enzyme|2.7.1.40}} {{KEGG compound|C00022}}
===Pyruvate decarboxylation to acetyl CoA===
[[Pyruvate decarboxylation]] by the [[pyruvate dehydrogenase complex]] produces [[acetyl-CoA]].
{{Enzymatic Reaction
|foward_enzyme=[[pyruvate dehydrogenase complex]]
|reverse_enzyme=
|substrate=pyruvate
|product=[[acetyl-CoA]]
|reaction_direction_(foward/reversible/reverse)=foward
|minor_foward_substrate(s)= [[CoA]] '''+''' NAD<sup>+</sup>
|minor_foward_product(s)= CO<sub>2</sub> '''+''' NADH '''+''' H<sup>+</sup>
|minor_reverse_substrate(s)=
|minor_reverse_product(s)=
|substrate_image=pyruvate_wpmp.png
|product_image=acetyl_co-A_wpmp.png
}}
===Pyruvate carboxylation to oxaloacetate===
Carboxylation by the [[pyruvate carboxylase]] produces [[oxaloacetate]].
{{Enzymatic Reaction
|foward_enzyme=[[pyruvate carboxylase]]
|reverse_enzyme=
|substrate=pyruvate
|product=[[oxaloacetate]]
|reaction_direction_(foward/reversible/reverse)=foward
|minor_foward_substrate(s)= ATP '''+''' CO<sub>2</sub>
|minor_foward_product(s)= ADP '''+''' P<sub>i</sub>
|minor_reverse_substrate(s)=
|minor_reverse_product(s)=
|substrate_image=pyruvate_wpmp.png
|product_image=Oxaloacetate_wpmp.png
}}
===Transamination by the alanine aminotransferase===
{{Enzymatic Reaction
|foward_enzyme=[[Alanine transaminase]]
|reverse_enzyme=
|substrate=pyruvate
|product=[[alanine]]
|reaction_direction_(foward/reversible/reverse)=reversible
|minor_foward_substrate(s)= [[Glutamate]]
|minor_foward_product(s)= [[α-ketoglutarate]]
|minor_reverse_substrate(s)= [[α-ketoglutarate]]
|minor_reverse_product(s)= [[Glutamate]]
|substrate_image=pyruvate_wpmp.png
|product_image=alanine_wpmp.png
}}
===Reduction to lactate===
Reduction by the [[lactate dehydrogenase]] produces [[lactate]].
{{Enzymatic Reaction
|foward_enzyme=[[lactate dehydrogenase]]
|reverse_enzyme=
|substrate=pyruvate
|product=[[lactate]]
|reaction_direction_(foward/reversible/reverse)=reversible
|minor_foward_substrate(s)= NADH
|minor_foward_product(s)= NAD<sup>+</sup>
|minor_reverse_substrate(s)= NAD<sup>+</sup>
|minor_reverse_product(s)= NADH
|substrate_image=pyruvate_wpmp.png
|product_image=Lactic-acid-skeletal.svg
}}
==Origin of life==
{{main|iron-sulfur world theory}}
Current evolutionary theory on the [[origin of life]] posits that the first organisms were anaerobic because the atmosphere of prebiotic Earth was almost devoid of oxygen. As such, requisite biochemical materials must have preceded life and recent experiments indicate that pyruvate can be synthesized [[Abiotic|abiotically]]. In vitro, [[iron sulfide]] at sufficient pressure and temperature [[catalyst|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==
* George D. Cody, Nabil Z. Boctor, Timothy R. Filley, Robert M. Hazen, James H. Scott, Anurag Sharma, Hatten S. Yoder Jr., "Primordial Carbonylated Iron-Sulfur Compounds and the Synthesis of Pyruvate," ''Science'', ''289'' (5483) (25 August 2000) pp. 1337 - 1340. [http://www.sciencemag.org/cgi/content/abstract/sci;289/5483/1337]
==External links==
{{commons|Pyruvic acid|Pyruvic acid}}
* [http://www.emphycorp.com/cancerprevention.html "Pyruvate in Cancer Prevention and Treatment"]
* [http://www.hopkinsmedicine.org/Press_releases/2004/10_14_04.html "ENERGY BLOCKER" KILLS BIG TUMORS IN RATS], research at Johns Hopkins on pyruvate
* [http://www.merriam-webster.com/dictionary/pyruvic%20acid "Latin uva grapes"]
{{Glycolysis}}
[[Category:Carboxylic acids]]
[[Category:Cellular respiration]]
[[Category:Exercise physiology]]
[[cs:Kyselina pyrohroznová]]
[[da:Pyruvat]]
[[de:Brenztraubensäure]]
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[[es:Ácido pirúvico]]
[[fr:Pyruvate]]
[[id:Asam piruvat]]
[[it:acido piruvico]]
[[lv:Pirovīnogskābe]]
[[lb:Pyruvat]]
[[hu:Piroszőlősav]]
[[nl:Pyrodruivenzuur]]
[[ja:ピルビン酸]]
[[pl:Kwas pirogronowy]]
[[pt:Ácido pirúvico]]
[[ru:Пировиноградная кислота]]
[[fi:Pyruvaatti]]
[[sv:Pyrodruvsyra]]
[[tr:Pirüvik asit]]
[[zh:丙酮酸]]