Catalase catalyzes the dismutation of hydrogen peroxide to water and oxygen. Perhaps all cells have catalase, but mitochondria of most cells lack catalase. Cardiac mitochondria are exceptional in having mt-catalase activity (rat heart mitochondria: Radi et al 1991; mouse heart mitochondria: Rindler et al 2013).
MitoPedia topics: Enzyme
Communicated by Gnaiger E (2015-03-05).
Application in HRR
Clt: Catalase (from bovine liver, lyophilized powder; 2,000-5,000 U/mg protein); Sigma C 9322; store at -20 °C.
Catalase is included in the mitochondrial respiration medium MiR06 (MiR06 = MiR05 plus catalase), so as to allow for re-oxygenation of the respiration medium (without lifting the stopper and risking the introduction of air bubbles) by addition of a small volume of a 200 mM stock solution of H2O2.
Preparation of catalase stock solution
- Stock solution: 112,000 U/mL (dissolved in MiR05)
- Example: 'Catalase lypophilized powder; 2,800 U/mg solid and 3,500 units/mg protein'
- 1) Use 'units/mg solid' for your calculations
- 2) Result: 40 mg catalase powder (2,800 U/mg) are dissolved in 1 mL MiR05 to obtain a catalase stock solution with 112,000 U/mL.
- 3) Divide into 0.2 mL portions.
- 4) Store frozen at -20 °C.
Unit definition: * Units of enzymatic activity (U) in µmol/min; assay used by Sigma Aldrich: ' One unit will decompose 1.0 μmole of H2O2 per min at pH 7.0 at 25 °C, while the H2O2 concentration falls from 10.3 to 9.2 mM, measured by the rate of decrease of A240. '
Oxygraph-2k manual titrations MiPNet09.12 O2k-Titrations
- Titration volume: 5 µL Ctl using a 25 µL syringe (2 mL O2k-chamber).
- Final concentration: 280 U/mL.