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.
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.
Unstable respiration while using Pyruvate as the only substrate
- Customer ID: AU Melbourne White C
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