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Difference between revisions of "Mitochondrial membrane potential"

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{{MitoPedia
{{MitoPedia
|abbr=mt-membrane potantial
|abbr=mtMP, Δ''ψ'' [V]
|description=The '''mitochondrial membrane potential''', mtMP, is the electric part of the protonmotive [[force]], Δ''p''<sub>H+</sub>.
 
Δ''ψ'' = Δ''p''<sub>H+</sub> - Δ''µ''<sub>H+</sub> / ''F''
 
mtMP or Δ''ψ'' is the potential difference across the inner mitochondrial (mt) membrane, expressed in the electric unit of volt [V]. Electric force of the mitochondrial membrane potential is the electric energy change per ‘motive’ electron or per electron moved across the transmembrane potential difference, with the number of ‘motive’ electrons expressed in the unit coulomb [C].
|info=[[Mitchell 1961 Nature]], [[Gnaiger 2014 Preface MiP2014]]
}}
}}
{{MitoPedia methods}}
Communicated by [[Gnaiger E]] 2012-10-05, edited 2016-02-06, 2017-09-05.
{{MitoPedia topics}}
:::: The chemical part of the protonmotive force, ''µ''<sub>H+</sub> / ''F'' stems from the difference of pH across the mt-membrane. It contains a factor that bridges the gap between the electric force [J/C] and the chemical force [J/mol]. This factor is the Faraday constant, ''F'', for conversion between electric force expressed in joules per coulomb or Volt [V=J/C] and chemical force with the unit joules per mole or Jol [Jol=J/mol],
This page is a guide to various wiki.oroboros.at pages that complement [http://www.oroboros.at/?O2k-multisensor-manual] with up-to-date information and discussions. The general manual for the OROBOROS Ion Selective Electrode system ([[ISE]] System) is in [http://www.oroboros.at/?O2k-multisensor [MiPNet15.03]]. While working with the potentiometric (pX) channel of the O2k, the general [[ESD|guidelines for avoiding damage to the oxygraph by ESD]] should be followed.  
 
:::::::: ''F'' = 96.4853 kJol/V = 96,485.3 C/mol


A rudimentary protocol for measuring mitochondrial membrane potential (MiPNet14.05), its mathematical appendix and the most up-to-date spreadsheet templates, DatLab templates, and DatLab demo files, can be found [http://www.oroboros.at/?Protocols_tpp-membranepotential here].
__TOC__
{{Template:Technical support integrated}}
== Different methods for measurements of mt-membrane potential ==


Before measuring membrane potential via [[TPP+]] is even started, the [[TPP+ inhibitory effect]] in the studied system should be explored.How to get from the measured TPP+ concentration to the mitochondrial membrane potential: [[Calculation of mitochondrial membrane potential from measurements with a TPP electrode]]. This covers also the influence of [[Unspecific binding]].
:::: mt-Membrane potential can either be measured in the [[O2k-FluoRespirometer]] fluorometrically by using the fluorophores [[TMRM]] or [[Safranin]], or potentiometrically with the [[O2k-TPP+ ISE-Module]] electrode by using the ion reporter [[TPP+]]. All mentioned ion indicator molecules inhibit respiration, which makes it essential to test the optimum concentration.


Practical difficulties in applying the method to permeabilized fibers are discussed in [[Mitochondrial membrane potential of permeabilized fibers]]. Some tips for [[Cleaning the TPP+ electrodes]]Some important performance parameters of the TPP electrode are summarized on this [http://www.oroboros.at/fileadmin/user_upload/MiP2010/MiP2010_Sumbalova_poster1.pdf poster]. In any way we hope you will join us for one of our [[TPP special interest group during an International Oxygraph Course]].
== High-resolution respirometry and mt-membrane potential ==


:::: The O2k-MultiSensor system provides a potentiometric and a fluorometric module for measurement of the mt-membrane potential.
::::» O2k-Manual TPP: [[MiPNet15.03 O2k-MultiSensor-ISE]]
::::» [[Tetraphenylphosphonium#O2k-technical_support |TPP: O2k-technical_support]]
::::» [[MiPNet20.13 Safranin mt-membranepotential]]
::::» [[TMRM#O2k-technical_support |TMRM: O2k-technical_support]]


== Mitochondrial membrane potential and anoxia ==
== Calculations ==


=== Question ===
::::* Data analysis of [[Mitochondrial membrane potential|mitochondrial membrane potential]]  estimation using various fluorescence dyes: [[MiPNet24.09 General Template for Mt-membrane Potential Analysis]] to calculate the relative mt-membrane potential values.


Can I use anoxia as a reference state for zero (minimum) mt-membrane potential in isolated mitochondria?  I want to run experiments in series without loosing the time for washing out inhibitors or uncouplers.  The protocol includes substrates and ADP.
::::* Data analysis of [[Mitochondrial membrane potential|mitochondrial membrane potential]]  estimation with safranin using DatLab 7.4: [[MiPNet24.08 Safranin Analysis Template]] to express the mt-membrane potential values in mV.


=== Answer ===
:::::* The calculation used to calculate the mt-membrane potential values are provided here complying with Oroboros transparancy policy, see the following page: [[Safranin]]


Anoxia should provide a good reference value for minimum mt-membrane potential. However, you should carry out a test experiment: After reaching anoxia, add oligomycin as a test for the possibility that ATPsynthase acts as a ATPase and thus maintains a mt-membrane potential in reversed mode of operation.  Then titrate uncoupler (FCCP) to collaps the mt-membrane potential under anoxia.
:::::* for detailed explanaition, see [[MiPNet24.11 mtMP calculation]]


Careful: Ethanol as a carrier for oligomycin and FCCP exerts a chemical side effect on the TPP+ signal, which has to be evaluated in a separate control experiment and subtracted from the experimental trace.
== [[SUITbrowser]] question: Mitochondrial membrane potential ==
:::: Several [[SUIT]] protocols are focused on the measurement of mt-membrane potential by potentiometric and fluorometric techniques.
:::: Use the [https://suitbrowser.oroboros.at/ SUITbrowser] to find the best protocol to answer this and other research questions.


=== See also ===
== Keywords: Force and membrane potential ==
[[Mitochondrial membrane potential]]
{{Keywords Force and membrane potential}}


[[ISE]]
{{MitoPedia concepts
|mitopedia concept=Respiratory state, Recommended, Ergodynamics
}}
{{MitoPedia methods
|mitopedia method=Respirometry, Fluorometry
}}
{{MitoPedia topics
|mitopedia topic=EAGLE
}}

Revision as of 14:29, 7 November 2019


high-resolution terminology - matching measurements at high-resolution


Mitochondrial membrane potential

Description

The mitochondrial membrane potential, mtMP, is the electric part of the protonmotive force, ΔpH+.

Δψ = ΔpH+ - ΔµH+ / F

mtMP or Δψ is the potential difference across the inner mitochondrial (mt) membrane, expressed in the electric unit of volt [V]. Electric force of the mitochondrial membrane potential is the electric energy change per ‘motive’ electron or per electron moved across the transmembrane potential difference, with the number of ‘motive’ electrons expressed in the unit coulomb [C].

Abbreviation: mtMP, Δψ [V]

Reference: Mitchell 1961 Nature, Gnaiger 2014 Preface MiP2014

Communicated by Gnaiger E 2012-10-05, edited 2016-02-06, 2017-09-05.
The chemical part of the protonmotive force, µH+ / F stems from the difference of pH across the mt-membrane. It contains a factor that bridges the gap between the electric force [J/C] and the chemical force [J/mol]. This factor is the Faraday constant, F, for conversion between electric force expressed in joules per coulomb or Volt [V=J/C] and chemical force with the unit joules per mole or Jol [Jol=J/mol],
F = 96.4853 kJol/V = 96,485.3 C/mol

Template NextGen-O2k.jpg


MitoPedia O2k and high-resolution respirometry: O2k-Open Support 



Different methods for measurements of mt-membrane potential

mt-Membrane potential can either be measured in the O2k-FluoRespirometer fluorometrically by using the fluorophores TMRM or Safranin, or potentiometrically with the O2k-TPP+ ISE-Module electrode by using the ion reporter TPP+. All mentioned ion indicator molecules inhibit respiration, which makes it essential to test the optimum concentration.

High-resolution respirometry and mt-membrane potential

The O2k-MultiSensor system provides a potentiometric and a fluorometric module for measurement of the mt-membrane potential.
» O2k-Manual TPP: MiPNet15.03 O2k-MultiSensor-ISE
» TPP: O2k-technical_support
» MiPNet20.13 Safranin mt-membranepotential
» TMRM: O2k-technical_support

Calculations

  • The calculation used to calculate the mt-membrane potential values are provided here complying with Oroboros transparancy policy, see the following page: Safranin

SUITbrowser question: Mitochondrial membrane potential

Several SUIT protocols are focused on the measurement of mt-membrane potential by potentiometric and fluorometric techniques.
Use the SUITbrowser to find the best protocol to answer this and other research questions.

Keywords: Force and membrane potential

Template:Keywords Force and membrane potential


MitoPedia concepts: Respiratory state, Recommended, Ergodynamics 


MitoPedia methods: Respirometry, Fluorometry 


MitoPedia topics: EAGLE