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| {{MitoPedia
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| |abbr=P
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| |description=[[File:Pyruvic_acid.jpg|left|80px|Pyruvic acid]]
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| '''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]].
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| |info=[[Gnaiger 2020 BEC MitoPathways]], [[MiPNet09.12 O2k-Titrations]]
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| }}
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| __TOC__
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| == Application in [[HRR]] ==
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| === General ===
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| {{Chemical_description
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| |abbr=P
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| |trivial name=Pyruvate
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| |complete name=pyruvic acid, sodium salt
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| |chem formula=C₃H₃O₃Na
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| |molar mass=110.0
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| |vendor=Sigma-Aldrich
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| |product number=P2256
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| |store at=4 °C
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| |sensitivity=
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| |cas=113-24-6
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| |h statements=H317, H319
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| |h info=may cause an allergic skin reaction, causes serious eye irritation
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| }}<!--::: '''P: Pyruvate''' (pyruvic acid, sodium salt, C<sub>3</sub>H<sub>3</sub>O<sub>3</sub>Na); Sigma P 2256, 25 g, store at 4 °C; M = 110.0 g·mol<sup>-1</sup>-->
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| :::: It is possible to weigh the powder beforehand in the Eppendorf-type tubes and store these tubes at 4 °C, to be diluted only on the day of use.
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| :::: After addition of H<sub>2</sub>O the pH of the Pyruvate solution is about 6. This is acceptable without pH-adjustment, because the titrated volumes are small and reaction media are buffered.
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| :::: 2021-03: The preparation instructions were updated to take into account the volume of the solute (P) (see: [[Volume_of_the_solute| Volume of the solute]]). The concentrations prepared following the former instructions (see Discussion section) are sufficiently high for SUIT protocol titrations.
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| === Preparation of stock solution ===
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| :::: '''2-mL O2k-chamber''': 200 µL in H<sub>2</sub>O
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| ::::# Prepare fresh everyday.
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| ::::# Weigh 44 mg of pyruvic acid directly into a 0.5 mL Eppendorf tube.
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| ::::# Add 180 µL H<sub>2</sub>O.
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| :::: '''0.5-mL O2k-chamber''': 200 µL in H<sub>2</sub>O
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| ::::# Prepare fresh everyday.
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| ::::# Weigh 55 mg of pyruvic acid directly into a 0.5 mL Eppendorf tube.
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| ::::# Add 175 µL H<sub>2</sub>O.
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| === Manual titrations ===
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| {{Titration instructions
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| |solvent= H<sub>2</sub>O
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| |stock storage cond= prepare fresh
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| |exp conc=5 mM
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| |lv titration vol=5
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| |lv conc=2 M
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| |lv syringe vol=25
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| |sv titration vol=1
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| |sv conc=2.5 M
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| |sv syringe vol=10
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| }}
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| <!--
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| :::» '''O2k manual titrations''' [[MiPNet09.12 O2k-Titrations]]
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| ::::* Titration volume ('''2-mL O2k-chamber'''): 5 µL using a 25 µL Hamilton syringe.
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| ::::* Final concentration: 5 mM.
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| :::» '''O2k manual titrations''' [[MiPNet09.12 O2k-Titrations]]
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| ::::* Titration volume ('''0.5-mL O2k-chamber'''): 1 µL using a 10 µL Hamilton syringe.
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| ::::* Final concentration: 5 mM.-->
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