Difference between revisions of "Pyruvate"
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|abbr=P | |abbr=P | ||
|description=[[File:Pyruvic_acid.jpg|left|80px|Pyruvic acid]] | |description=[[File:Pyruvic_acid.jpg|left|80px|Pyruvic acid]] | ||
'''Pyruvic acid''', C<sub>3</sub>H<sub>4</sub>O<sub>3</sub>, is an alpha-keto monocarboxylic acid which occurs under physiological conditions mainly as the anion '''pyruvate<sup>-</sup>, P''', with ''p''K<sub>a</sub> = 2.5. Pyruvate is formed in glycolysis from phosphoenolpyruvate. In the cytosol, pyruvate is a substrate of [[lactate dehydrogenase]]. Pyruvate enters the mitochondrial matrix via a specific low ''K''<sub>m</sub>' H<sup>+</sup>/monocarboxylate cotransporter known as the [[pyruvate carrier]]. Similarly, the plasma membrane of many cell types has H<sup>+</sup>/monocarboxylate cotransporter activity and pyruvate can thus be added as a substrate to living cells. In the mt-matrix the oxidative decarboxylation of pyruvate is catalyzed by [[pyruvate dehydrogenase]] and yields [[acetyl-CoA]]. Pyruvate competitively reverses the inhibition of [[Complex IV | cytochrome ''c'' oxidase]] by [[cyanide]]. Pyruvate is an antioxidant reacting with [[hydrogen peroxide]]. | '''Pyruvic acid''', C<sub>3</sub>H<sub>4</sub>O<sub>3</sub>, is an alpha-keto monocarboxylic acid which occurs under physiological conditions mainly as the anion '''pyruvate<sup>-</sup>, P''', with ''p''K<sub>a</sub> = 2.5. Pyruvate is formed in glycolysis from phosphoenolpyruvate. In the cytosol, pyruvate is a substrate of [[lactate dehydrogenase]]. Pyruvate enters the mitochondrial matrix via a specific low ''K''<sub>m</sub>' H<sup>+</sup>/monocarboxylate cotransporter known as the [[pyruvate carrier]]. Similarly, the plasma membrane of many cell types has H<sup>+</sup>/monocarboxylate cotransporter activity and pyruvate can thus be added as a substrate to living cells. In the mt-matrix the oxidative decarboxylation of pyruvate is catalyzed by [[pyruvate dehydrogenase]] and yields [[acetyl-CoA]]. Pyruvate alone cannot support respiration of [[Mitochondrial preparations|mt-preparations]] from most tissues. Pyruvate competitively reverses the inhibition of [[Complex IV | cytochrome ''c'' oxidase]] by [[cyanide]]. Pyruvate is an antioxidant reacting with [[hydrogen peroxide]]. | ||
|info=[[Gnaiger 2014 MitoPathways]], [[MiPNet09.12 O2k-Titrations]] | |info=[[Gnaiger 2014 MitoPathways]], [[MiPNet09.12 O2k-Titrations]] | ||
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'''Question:''' | '''Question:''' | ||
I am evaluating mitochondrial respiration from ''Drosophila melanogaster'' using Pyruvate, ADP, and Cytochrome C. However, I do not achieve a steady state level in OXPHOS. | |||
Any advice would be appreciated. The data is attached (2019-07-17). | Any advice would be appreciated. The data is attached (2019-07-17). | ||
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[[File:Ticket2019072631000015.png|700px|center]] | [[File:Ticket2019072631000015.png|700px|center]] | ||
'''Answer:''' | |||
Pyruvate alone is not sufficient to support NADH-linked respiration. In order to do so you will need to combine at least a 2<sup>nd</sup> NADH-linked substrate (''e.g.,'' Glutamate, Malate...). ''See'' [[Gnaiger 2014 MitoPathways]] | |||
Additionally, you may consult some of the publications from ''Drosophila melanogaster'' mitochondria:[[O2k-Publications:_Drosophila]] | |||
Revision as of 14:38, 20 March 2020
- high-resolution terminology - matching measurements at high-resolution
Pyruvate
Description
Pyruvic acid, C3H4O3, is an alpha-keto monocarboxylic acid which occurs under physiological conditions mainly as the anion pyruvate-, P, with pKa = 2.5. Pyruvate is formed in glycolysis from phosphoenolpyruvate. In the cytosol, pyruvate is a substrate of lactate dehydrogenase. Pyruvate enters the mitochondrial matrix via a specific low Km' H+/monocarboxylate cotransporter known as the pyruvate carrier. Similarly, the plasma membrane of many cell types has H+/monocarboxylate cotransporter activity and pyruvate can thus be added as a substrate to living cells. In the mt-matrix the oxidative decarboxylation of pyruvate is catalyzed by pyruvate dehydrogenase and yields acetyl-CoA. Pyruvate alone cannot support respiration of mt-preparations from most tissues. Pyruvate competitively reverses the inhibition of cytochrome c oxidase by cyanide. Pyruvate is an antioxidant reacting with hydrogen peroxide.
Abbreviation: P
Reference: Gnaiger 2014 MitoPathways, MiPNet09.12 O2k-Titrations
MitoPedia topics:
Substrate and metabolite
Application in HRR
- P: Pyruvate (pyruvic acid, sodium salt, C3H3O3Na); Sigma P 2256, 25 g, store at 4 °C; FW = 110.0
- Preparation of 2 M stock solution (dissolved in H2O)
- Prepare fresh everyday.
- Weigh 44 mg of pyruvic acid directyl into a 0.5 mL Eppendorf tube.
- Add 0.2 mL H2O.
- Adjust pH to 7.0.
- O2k manual titrations MiPNet09.12 O2k-Titrations
- Titration volume: 5 µL using a 25 µL syringe (2 mL O2k-chamber).
- Final concentration: 5 mM.
Troubleshooting
Unstable respiration while using Pyruvate as the only substrate
- Customer ID: AU Melbourne White C
Question:
I am evaluating mitochondrial respiration from Drosophila melanogaster using Pyruvate, ADP, and Cytochrome C. However, I do not achieve a steady state level in OXPHOS.
Any advice would be appreciated. The data is attached (2019-07-17).
Answer: Pyruvate alone is not sufficient to support NADH-linked respiration. In order to do so you will need to combine at least a 2nd NADH-linked substrate (e.g., Glutamate, Malate...). See Gnaiger 2014 MitoPathways
Additionally, you may consult some of the publications from Drosophila melanogaster mitochondria:O2k-Publications:_Drosophila
