Rotenone

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Rotenone

Description

Rotenone is an inhibitor of Complex I (CI) and thus inhibits NADH oxidation. It inhibits the transfer of electrons from iron-sulfur clusters in CI to ubiquinone via binding to the ubiquinone binding site of CI. See also Succinate pathway.

Abbreviation: Rot

Reference: Gnaiger 2020 BEC MitoPathways, MiPNet03.02

Application in HRR

Rot: Rotenone ( C23H22O6), Sigma-Aldrich: R8875, store at RT (light sensitive), CAS: 83-79-4, M = 394.42 gΒ·mol-1
Hazard statements: H300, H330, H315, H319, H335, H410; fatal if swallowed, fatal if inhaled, causes skin irritation, causes serious eye irritation, may cause respiratory irritation, very toxic to aquatic life with long-lasting effects
Caution: In solution and exposed to light and air, rotenone decomposes losing toxicity within days, see PubChem for details.


Preparation of 1 mM stock solution (dissolved in ethanol abs.) for 2-mL O2k-chamber:
  1. Weigh about 1 mg of rotenone.
  2. Calculate the amount of ethanol abs. needed: 1 mL of ethanol abs. per 0.39 mg of rotenone.
  3. Rotenone does not dissolve easily in ethanol. Warming to 35Β°C and an ultrasonic bath will improve solubility.
  4. Divide into 100 Β΅L aliquots (use dark glass vials).
  5. Store frozen at -20 Β°C.
Β» O2k manual titrations MiPNet09.12 O2k-Titrations
  • Titration volume (2-mL O2k-chamber): 1 Β΅L using a 10 Β΅L Hamilton syringe.
  • Final concentration: 0.5 Β΅M.


Preparation of 0.25 mM stock solution (dissolved in ethanol abs.) for 0.5-mL O2k-chamber:
  1. Take 50 Β΅L of the 1 mM stock solution.
  2. Add 150 Β΅L of ethanol abs.
Β» O2k manual titrations MiPNet09.12 O2k-Titrations
  • Titration volume (0.5-mL O2k-chamber): 1 Β΅L using a 10 Β΅L Hamilton syringe.
  • Final concentration: 0.5 Β΅M.


Microalgae applications
For the specific case of microalgal cells it is recommended to prepare higher concentration:
Preparation of 5.5 mM stock solution (dissolved in ethanol abs.)
  1. Weigh 4.4 mg of rotenone and dissolve in 2 mL of ethanol abs.
  2. Divide into 200 Β΅L aliquots (use dark glass vials).
  3. Store frozen at -20 Β°C.
Β» O2k manual titrations MiPNet09.12 O2k-Titrations
  • Titration volume (2-mL O2k-chamber): 15 Β΅L using a 25 Β΅L Hamilton syringe.
  • Experimental concentration: 41 Β΅M.


Inhibition of CI by rotenone

  • Fato R, Bergamini C, Bortolus M, Maniero AL, Leoni S, Ohnishi T, Lenaz G (2009) Differential effects of mitochondrial Complex I inhibitors on production of reactive oxygen species. Biochim Biophys Acta 1787:384–92. >>PMC2724837

History

  • Up to 2006, rotenone was added at a high final concentration (0.5 Β΅M), hence a 0.5 mM stock solution was prepared. Since 0.05 Β΅M may be fully inhibiting, we suggested to use a stock solution at lower concentration (0.1 mM), to reduce the problem of rotenone retention. The 2006 edition listed a 0.2 mM stock solution, but the amount added to 10 mL ethanol was given for a 0.15 mM stock solution. Our recent rotenone titrations with permeabilized muscle fibers, however, confirmed that the originally proposed higher rotenone concentration is actually required for full inhibition.


MitoPedia topics: Inhibitor 

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