Cyanide: Difference between revisions

Latest revision as of 09:51, 10 June 2021

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):

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

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 |info=[[MiPNet09.12]]
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+{{MitoPedia O2k and high-resolution respirometry|type=Inhibitor ETS
+}}
+{{MitoPedia topics
+|mitopedia topic=Inhibitor
+}}
 __TOC__
 == Application in [[HRR]] ==
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 ::::* [[alternative oxidase]]
-:::: '''Kcn'''(KCN): Fluka 60178, 100 g, store at R.T.; FW = 65.12; '''Trizma base''': Sigma T6066, 100 g, store at R.T.; FW = 121.14
-:::: <span style="color:#8B008B"> '''Caution:''' KCN is photosensitive and hygroscopic; HCN is volatile and very toxic! It is recommended to prepare fresh KCN solution although it can be safely stored at -20°C. To avoid KCN evaporation, it is recommended to use alkaline buffers (such as 45 mM Trizma base, pH >10).</span>
+=== Preparation of KCN stock ===
+{{Chemical_description
+|abbr=KCN
+|trivial name=Cyanide
+|complete name=Potassium cyanide
+|chem formula=KCN
+|molar mass=65.12
+|vendor=Sigma-Aldrich
+|product number=60178
+|store at=RT
+|sensitivity=
+|cas=151-50-8
+|h statements=H290, H300, H330, H310, H372, H400, H410
+|h info=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
+}}<!--:::: '''Kcn'''(KCN): Sigma 60178, 100 g, store at R.T.; M = 65.12 g·mol<sup>-1</sup>.-->
+:::: <span style="color:#8B008B"> '''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 [https://pubchem.ncbi.nlm.nih.gov/compound/9032#section=Storage-Conditions PubChem]</span>
+:::: '''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 45 mM Trizma base:'''
+:::: ''' Preparation of 0.5 M KCN stock solution''' (dissolved in H<sub>2</sub>O):
-::::# Weigh 545 mg of Trizma base
-::::# Dissolve it in 100 mL of H<sub>2</sub>0.
+::::# Weigh 32.6 mg of KCN.
-::::''' Preparation of 20 mM KCN stock solution ''' (in 45 mM Trizma base) for '''2-mL O2k-chamber''':
+::::# Dissolve in 1 ml H<sub>2</sub>O.
-::::# Weigh 5.2 mg of KCN and dissolve in 4 mL of 45 mM Trizma base.
+::::# 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 500 µL aliquots (use dark glass vials).
+::::# Divide into 0.2 mL portions
-::::# Store frozen at -20 °C.
+::::# Store at -20 °C.
 :::» '''O2k manual titrations'''  [[MiPNet09.12 O2k-Titrations]]
-::::* Titration volume ('''2-mL O2k-chamber'''): 100 µL using a 100 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.
-:::: '''Preparation of 0.25 M KCN stock solution''' (in 45 mM Trizma base) for '''0.5-mL O2k-chamber''':
-::::# Weigh 16,28 mg of KCN and dissolve in 1 mL of 45 mM Trizma base.
-::::# Divide into 200 µL aliquots (use dark glass vials).
-::::# Store frozen at -20 °C.
-:::» '''O2k manual titrations'''  [[MiPNet09.12 O2k-Titrations]]
-::::* Titration volume ('''0.5-mL O2k-chamber'''): 2 µL using a 10 µL Hamilton syringe.
-::::* Final concentration: 1 mM.
 {{MitoPedia O2k and high-resolution respirometry|type=Inhibitor ETS
 }}