Pyruvate: Difference between revisions
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|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 competitively reverses the inhibition of [[Complex IV | cytochrome ''c'' oxidase]] by [[cyanide]]. Pyruvate is an antioxidant reacting with [[hydrogen peroxide]]. | ||
|info=[[Gnaiger | |info=[[Gnaiger 2020 BEC MitoPathways]], [[MiPNet09.12 O2k-Titrations]] | ||
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[[File:Ticket2019072631000015.png|700px|center]] | [[File:Ticket2019072631000015.png|700px|center]] | ||
:::* <div>'''Answer:'''</div><div>Pyruvate alone is not sufficient to support NADH-linked respiration. In order to do so you need to combine pyruvate with at least a second NADH-linked substrate ( | :::* <div>'''Answer:'''</div><div>Pyruvate alone is not sufficient to support NADH-linked respiration. In order to do so you need to combine pyruvate with at least a second NADH-linked substrate (e.g. Malate) or use a more complex combination of substrates (''e.g.,'' Pyruvate&Glutamate&Malate). See Fig. 5.9. in [https://wiki.oroboros.at/images/f/fc/Gnaiger_2014_Mitochondr_Physiol_Network_MitoPathways.pdf Gnaiger 2020 BEC MitoPathways] | ||
:::: Additionally, you may consult some of the publications from Drosophila melanogaster mitochondria: [[O2k-Publications:_Drosophila]] | :::: Additionally, you may consult some of the publications from Drosophila melanogaster mitochondria: [[O2k-Publications:_Drosophila]] |
Revision as of 19:29, 1 January 2021
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 competitively reverses the inhibition of cytochrome c oxidase by cyanide. Pyruvate is an antioxidant reacting with hydrogen peroxide.
Abbreviation: P
Reference: Gnaiger 2020 BEC MitoPathways, MiPNet09.12 O2k-Titrations
Application in HRR
- P: Pyruvate (pyruvic acid, sodium salt, C3H3O3Na); Sigma P 2256, 25 g, store at 4 ยฐC; FW = 110.0
- It is possible to weigh the powder beforehand in the Eppendorf-type tubes and store these tubes at 4 ยฐC, to be diluted only on the day of use.
- P: Pyruvate (pyruvic acid, sodium salt, C3H3O3Na); Sigma P 2256, 25 g, store at 4 ยฐC; FW = 110.0
- Preparation of 2 M stock solution (dissolved in H2O) for use in 2-mL O2k-chamber:
- Prepare fresh everyday.
- Weigh 44 mg of pyruvic acid directly into a 0.5 mL Eppendorf tube.
- Add 0.2 mL H2O.
- Adjust pH to 7.0.
- ยป O2k manual titrations MiPNet09.12 O2k-Titrations
- Titration volume (2-mL O2k-chamber): 5 ยตL using a 25 ยตL Hamilton syringe.
- Final concentration: 5 mM.
- Preparation of 2.5 M stock solution (dissolved in H2O) for use in 0.5-mL O2k-chamber:
- Prepare fresh everyday.
- Weigh 55 mg of pyruvic acid directly into a 0.5 mL Eppendorf tube.
- Add 0.2 mL H2O.
- Adjust pH to 7.0.
- ยป O2k manual titrations MiPNet09.12 O2k-Titrations
- Titration volume (0.5-mL O2k-chamber): 1 ยตL using a 10 ยตL Hamilton syringe.
- 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 need to combine pyruvate with at least a second NADH-linked substrate (e.g. Malate) or use a more complex combination of substrates (e.g., Pyruvate&Glutamate&Malate). See Fig. 5.9. in Gnaiger 2020 BEC MitoPathways
- Additionally, you may consult some of the publications from Drosophila melanogaster mitochondria: O2k-Publications:_Drosophila
MitoPedia topics:
Substrate and metabolite