Cyanide

high-resolution terminology - matching measurements at high-resolution

Cyanide

Description

Cyanide (usually added as KCN) is a competitive inhibitor of cytochcrome c oxidase (CIV). Inhibition is reversed by pyruvate and high oxygen levels.

Abbreviation: KCN

Reference: MiPNet09.12

MitoPedia topics: Inhibitor 

Application in HRR

Inhibitor titrations, CIV-assay, alternative oxidase and ROX

• Cyanide and determination of residual oxygen consumption (ROX).
• Complex IV assay
• alternative oxidase

Preparation of KCN stock

KCN: Cyanide (Potassium cyanide; KCN), Sigma-Aldrich: 60178, store at RT, CAS: 151-50-8, M = 65.12 g·mol^-1

Hazard statements: H290, H300, H330, H310, H372, H400, H410; may be corrosive to metals, fatal if swallowed, fatal if inhaled, fatal in contact with skin, causes damage to organs through prolonged or repeated exposure (thyroid), very toxic to aquatic life, very toxic to aquatic life with long-lasting effects

Caution: Very toxic! Protect from light, store in a cool, dry, well-ventilated location. Separate from water, acids, and carbon dioxide. For details refer to PubChem

Caution: In April 2019 a change in the procedure for preparing the KCN was done that recommended to prepare 20 mM KCN stock and titrate 100 µL. 2021-01-22: after discussions on KCN toxicity we recommend to prepare of 0.5 M KCN stock solutions.

Preparation of 0.5 M KCN stock solution (dissolved in H₂O):

1. Weigh 32.6 mg of KCN.
2. Dissolve in 1 ml H₂O.
3. The pH of the solution is basic. Since the titration amount is low and HCN may evaporate during pH adjustment with HCl, the pH is not adjusted.
4. Divide into 0.2 mL portions
5. Store at -20 °C.

» O2k manual titrations MiPNet09.12 O2k-Titrations

• Titration volume (2-mL O2k-chamber): 4 µL using a 10 µL Hamilton syringe.
• Titration volume (0.5-mL O2k-chamber): 1 µL using a 10 µL Hamilton syringe.
• Final concentration: 1 mM.

MitoPedia topics: Inhibitor