Difference between revisions of "Cyanide"

Revision as of 13:12, 29 January 2021

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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

Last update 2021-01-22

Inhibitor titrations, CIV-assay, alternative oxidase and ROX

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

Caution: Due to a confusion, a change in the procedure for preparing the KCN was done in April 2019 that recommended to prepare 20 mM KCN stock and titrate 100 µL. This now has been corrected to our previous recommendation of 1 M KCN stock solutions

Preparation of KCN stock

Kcn(KCN): Fluka 60178, 100 g, store at R.T.; FW = 65.12.

Caution: KCN is photosensitive and hygroscopic; HCN is volatile and very toxic!

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

Weigh 32.6 mg of KCN.
Dissolve in 1 ml H₂O.
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.
Divide into 0.2 mL portions
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

@@ Line 25: / Line 25: @@
 :::: '''Kcn'''(KCN): Fluka 60178, 100 g, store at R.T.; FW = 65.12.
-:::: <span style="color:#8B008B"> '''Caution:''' KCN is photosensitive and hygroscopic; KCN is volatile and very toxic! </span>
+:::: <span style="color:#8B008B"> '''Caution:''' KCN is photosensitive and hygroscopic; HCN is volatile and very toxic! </span>
-:::: ''' Preparation of 1 M KCN stock solution ''' for '''2-mL O2k-chamber'''
+:::: ''' Preparation of 0.5 M KCN stock solution''' (dissolved in H<sub>2</sub>O):
+::::# Weigh 32.6 mg of KCN.
+::::# Dissolve in 1 ml H<sub>2</sub>O.
+::::# 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.
+::::# Divide into 0.2 mL portions
+::::# Store at -20 °C.
-::::# Weigh 13 mg of KCN.
-::::# Dissolve in 0.2 ml H<sub>2</sub>O.
-::::# The pH of the solution may be very alkaline - adjust to physiological pH with HCl.
 :::» '''O2k manual titrations'''  [[MiPNet09.12 O2k-Titrations]]
-::::* Titration volume ('''2-mL O2k-chamber'''): 2 µL using a 10 µL Hamilton syringe.
+::::* 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.