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Difference between revisions of "State 2"

From Bioblast
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|abbr=ROX<sub>D</sub>
|abbr=ROX<sub>D</sub>
|description=[[File:ROX.jpg |link=Residual oxygen consumption]] Substrate limited state of [[residual oxygen consumption]], after addition of [[ADP]] to isolated mitochondria suspended in mitochondrial respiration medium in the absence of reduced substrates (ROX<sub>D</sub>).  Residual endogenous substrates are oxidized during a transient stimulation of oxygen flux by ADP. The peak – supported by endogenous substrates – is, therefore, a pre-steady state phenomenon preceding State 2. Subsequently oxygen flux declines to a low level (or zero) at the steady '''State 2''' ([[Chance_1955_JBC-III|Chance and Williams 1955]]). ADP concentration (D) remains high during ROX<sub>D</sub>.
|description=[[File:ROX.jpg |link=Residual oxygen consumption]] Substrate limited state of [[residual oxygen consumption]], after addition of [[ADP]] to isolated mitochondria suspended in mitochondrial respiration medium in the absence of reduced substrates (ROX<sub>D</sub>).  Residual endogenous substrates are oxidized during a transient stimulation of oxygen flux by ADP. The peak – supported by endogenous substrates – is, therefore, a pre-steady state phenomenon preceding State 2. Subsequently oxygen flux declines to a low level (or zero) at the steady '''State 2''' ([[Chance_1955_JBC-III|Chance and Williams 1955]]). ADP concentration (D) remains high during ROX<sub>D</sub>.
|info=[[Chance 1955 JBC-III]], [http://www.oroboros.at/?Gnaiger_2012_MitoPathways Gnaiger 2012 MitoPathways]
|info=[[Chance 1955 JBC-III]], [[Gnaiger 2014 MitoPathways]]
|type=Respiration
|type=Respiration
}}
}}
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State 2 is equivalent to residual oxygen consumption, ROX.  ''We have sought independent controls on whether State 2 corresponds to complete oxidation of the system. It is logical that this be so, for respiration is zero in State 2 because substrate, not phosphate acceptor, is limiting'' (Chance and Williams 1955).   
State 2 is equivalent to residual oxygen consumption, ROX.  ''We have sought independent controls on whether State 2 corresponds to complete oxidation of the system. It is logical that this be so, for respiration is zero in State 2 because substrate, not phosphate acceptor, is limiting'' (Chance and Williams 1955).   


The State 2 and 4 terminology has become confusing, with a misunderstanding of the respiratory states introduced by Chance and Williams: ‘.. the controlled respiration prior to addition of ADP, which is strictly termed “state 2”, is functionally the same as state 4, and the latter term is usually used for both states’ (Nicholls and Ferguson 1992). Alchemy has a tradition of using the same term for multiple meanings and different terms for the same.  A termonological extension from integers to the fraction 3½ has been suggested to indicate an intermediate mitochondrial energy state somewhere between States 3 and 4. Paradoxically, a fractional numbering system (real numbers of mathematics) would suggest that ADP-activated hypoxia were intermediate between States 3.0 and 5.0, i.e. State 4.0. This state of terminology requires fundamental reconsideration for clarification, particularly for extending bioenergetics to mitochondrial respiratory physiology and OXPHOS analysis.
A numerical sequence of respiratory states has been introduced by Chance and Williams. The State 2 and 4 terminology, however, has become confusing and misunderstood: ‘.. the controlled respiration prior to addition of ADP, which is strictly termed “state 2”, is functionally the same as state 4, and the latter term is usually used for both states’ (Nicholls and Ferguson 1992). Alchemy has a tradition of using the same term for multiple meanings and different terms for the same.  A termonological extension from integers to the fraction 3½ has been suggested to indicate an intermediate mitochondrial energy state somewhere between States 3 and 4. Paradoxically, a fractional numbering system (real numbers of mathematics) would suggest that ADP-activated hypoxia were intermediate between States 3.0 and 5.0, i.e. State 4.0. This state of terminology requires fundamental reconsideration for clarification, particularly for extending bioenergetics to mitochondrial respiratory physiology and OXPHOS analysis.
* ''More details:'' >> [[LEAK respiration]]
* ''More details:'' »[[LEAK respiration]]

Revision as of 01:40, 22 May 2015


high-resolution terminology - matching measurements at high-resolution


State 2

Description

ROX.jpg Substrate limited state of residual oxygen consumption, after addition of ADP to isolated mitochondria suspended in mitochondrial respiration medium in the absence of reduced substrates (ROXD). Residual endogenous substrates are oxidized during a transient stimulation of oxygen flux by ADP. The peak – supported by endogenous substrates – is, therefore, a pre-steady state phenomenon preceding State 2. Subsequently oxygen flux declines to a low level (or zero) at the steady State 2 (Chance and Williams 1955). ADP concentration (D) remains high during ROXD.

Abbreviation: ROXD

Reference: Chance 1955 JBC-III, Gnaiger 2014 MitoPathways


MitoPedia methods: Respirometry, Spectrophotometry 


MitoPedia topics: "Respiratory state" is not in the list (Enzyme, Medium, Inhibitor, Substrate and metabolite, Uncoupler, Sample preparation, Permeabilization agent, EAGLE, MitoGlobal Organizations, MitoGlobal Centres, ...) of allowed values for the "MitoPedia topic" property. Respiratory state"Respiratory state" is not in the list (Enzyme, Medium, Inhibitor, Substrate and metabolite, Uncoupler, Sample preparation, Permeabilization agent, EAGLE, MitoGlobal Organizations, MitoGlobal Centres, ...) of allowed values for the "MitoPedia topic" property. 

State 2: towards a concept-linked terminology of respiratory states

State 2 is equivalent to residual oxygen consumption, ROX. We have sought independent controls on whether State 2 corresponds to complete oxidation of the system. It is logical that this be so, for respiration is zero in State 2 because substrate, not phosphate acceptor, is limiting (Chance and Williams 1955).

A numerical sequence of respiratory states has been introduced by Chance and Williams. The State 2 and 4 terminology, however, has become confusing and misunderstood: ‘.. the controlled respiration prior to addition of ADP, which is strictly termed “state 2”, is functionally the same as state 4, and the latter term is usually used for both states’ (Nicholls and Ferguson 1992). Alchemy has a tradition of using the same term for multiple meanings and different terms for the same. A termonological extension from integers to the fraction 3½ has been suggested to indicate an intermediate mitochondrial energy state somewhere between States 3 and 4. Paradoxically, a fractional numbering system (real numbers of mathematics) would suggest that ADP-activated hypoxia were intermediate between States 3.0 and 5.0, i.e. State 4.0. This state of terminology requires fundamental reconsideration for clarification, particularly for extending bioenergetics to mitochondrial respiratory physiology and OXPHOS analysis.