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Difference between revisions of "State 2"

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{{MitoPedia
{{MitoPedia
|abbr=ROX<sub>D</sub>
|abbr=ROX<sub>D</sub>
|description=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 2020 BEC MitoPathways]]
|type=Respiration
}}
}}
{{MitoPedia methods
{{MitoPedia concepts
|mitopedia method=Respirometry, Spectrophotometry
|mitopedia concept=Respiratory state, Find
|type=Respiration
}}
}}
{{MitoPedia topics
{{MitoPedia topics
|mitopedia topic=Respiratory state
|mitopedia topic=EAGLE
|type=Respiration
}}
}}
==An alternative protocol==
Communicated by [[Gnaiger E]] 2010-12-20, edited 2016-02-21.
== ROX versus LEAK: towards a concept-linked terminology of respiratory states ==


Sequential addition of (1) mitochondria, (2) ADP, and (3) reduced substrates is the basis of the original [[State 1]]-[[State 2|2]]-[[State 3|3]] definitions of respiratory states (Chance and Williams 1955 part III, 1956), where State 2 is zero respiration or residual oxygen consumption in the absence of substrate. An alternative protocol is well established, as shown e.g. by the classical Fig. 5A (Chance and Williams 1955 part I): 600 µM ADP is added after a state described as ‘Aerobic mitochondria plus succinate’. That state was never defined as ‘State 2’ by Brit Chance. Later Estabrook (1967) made this protocol more popular, with addition of substrate before any ADP or ATP was added.
::: '''ROX'''
:::: 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_1955_JBC-III|Chance and Williams 1955]]).


In this alternative protocol, a respiratory [[LEAK]] state is induced as the second respiratory state of isolated mitochondria, permeabilized tissues, or permeabilized cells, adding the mitochondrial preparation to respiration medium containing inorganic phosphate ([[State 1]]), then adding reduced substrate (no external adenylates). This second state (Estabrook 1967) is a non-phosphorylating LEAK state, ''L''<sub>N</sub> (N for no adenylates; Gnaiger 2009), when substrate-saturated respiration compensates for the proton leak (mainly) in the absence of ADP.
::: '''Clarification'''
:::: A numerical sequence of terms defining 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.


In contradiction to the original definition of State 2 ([[ROX]]), yet with reference to Chance and Williams (1956), 'State 2' has later been used for describing this functionally different state of [[LEAK respiration]]:
::: '''More details'''
 
::::» [[LEAK respiration]]
::''State 2: substrate added, respiration low due to lack of ADP.  .. 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 & Ferguson 1992).
::::» [[MitoPedia: Respiratory states]]
 
To overcome the termonological confusion persisting in the scientific literature, the respiratory coupling states of [[LEAK respiration]], [[OXPHOS capacity]] and [[ETS capacity]] are distinguished from residual oxygen consumption ([[ROX]]; [[Gnaiger 2009 Int J Biochem Cell Biol|Gnaiger 2009]]).
 
==References==
 
Chance B, Williams GR (1955) Respiratory enzymes in oxidative phosphorylation. I. Kinetics of oxygen utilization. J Biol Chem 217: 383-393.
 
Chance B, Williams GR (1955) Respiratory enzymes in oxidative phosphorylation. III. The steady state. J Biol Chem 217: 409-427.
 
Chance B, Williams GR (1956) The respiratory chain and oxidative phosphorylation. Adv Enzymol 17: 65-134.
 
Estabrook R (1967) Mitochondrial respiratory control and the polarographic measurement of ADP:O ratios. Methods Enzymol 10: 41-47.
 
Gnaiger E (2009) Capacity of oxidative phosphorylation in human skeletal muscle. New perspectives of mitochondrial physiology. [[Gnaiger 2009 Int J Biochem Cell Biol|Int J Biochem Cell Biol 41: 1837–1845. PMID: 19467914]]
 
Nicholls DG, Ferguson SJ (2002) Bioenergetics 3. Academic Press, London. 287 pp.

Latest revision as of 17:45, 1 January 2021


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 2020 BEC MitoPathways


MitoPedia concepts: Respiratory state, Find 


MitoPedia topics: EAGLE 

Communicated by Gnaiger E 2010-12-20, edited 2016-02-21.

ROX versus LEAK: towards a concept-linked terminology of respiratory states

ROX
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).
Clarification
A numerical sequence of terms defining 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
» MitoPedia: Respiratory states