Oxygen flux

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Oxygen flux


Oxygen flux, JO2, is a specific quantity. Oxygen flux is oxygen flow, IO2 [mol路s-1 per system] (an extensive quantity), divided by system size. Flux may be volume-specific (flow per volume [pmol路s-1路mL-1]), mass-specific (flow per mass [pmol路s-1路mg-1]), or marker-specific (flow per mtEU). Oxygen flux (e.g., per body mass, or per cell volume) is distinguished from oxygen flow (per number of objects, such as cells), IO2 [mol路s-1路x-1]. These are different forms of normalization of rate.

Abbreviation: JO2

Reference: BEC 2020.1, Gnaiger 2020 BEC MitoPathways, Gnaiger 1993 Pure Appl Chem, Renner 2003 Biochim Biophys Acta

Contributed by Gnaiger E (2020-01-15)

Which SI units should be used?

  • The SI unit for volume
1000 L = 1 m3
1 L = 1 dm3
1 mL = 1 cm3
1 碌L = 1 mm3
  • Convert various units of volume-specific oxygen flux, JO2, to SI units [nmol路s-1路L-1] = [pmol路s-1路mL-1]
1 碌mol O2鈭檓in-1鈭橪-1 鈭 [1000 nmol鈭(1 碌mol)-1] 鈭 [1 min鈭(60 s)-1] = 16.67 nmol O2鈭檚-1鈭橪-1
1 nmol O2鈭檓in-1鈭檓L-1 鈭 [1000 pmol鈭(1 nmol)-1] 鈭 [1 min鈭(60 s)-1] = 16.67 pmol O2鈭檚-1鈭檓L-1
1 nmol O2鈭檋-1鈭檓L-1 鈭 [1000 pmol鈭(1 nmol)-1] 鈭 [1 min鈭(60 s)-1] 鈭 [1 h鈭(60 min)-1] = 0.2778 pmol O2鈭檚-1鈭檓L-1
1 natom O鈭檚-1鈭橪-1 鈭 [1 nmol O2鈭(2 natm O)-1] = 0.5 nmol O2鈭檚-1鈭橪-1
1 natom O鈭檓in-1鈭橪-1 鈭 [1000 pmol O2鈭(2 natom O)-1] 鈭 [1 min鈭(60 s)-1] = 8.33 pmol O2鈭檚-1鈭橪-1
  • Convert VO2max/M from ergometric to SI units
1 mL O2鈭檓in-1鈭檏g-1 (at STPD) 鈭 [1000 碌mol鈭(22.392 mL)-1] 鈭 [1 min鈭(60 s)-1] = 0.744 碌mol O2鈭檚-1鈭檏g-1
  • There is a difference between oxygen flux per volume and oxygen concentration change per time
The oxygen concentration change per time (= rate of concentration change) is expressed in units [碌mol O2鈭橪-1鈭檚-1].
By definition the rate of concentration change is zero in an open system at steady-state, when the concentration in the system does not change at any respiratory flux by the sample enclosed in the open system.
Oxygen flux per volume (= volume-specific oxygen flux) is expressed in units [碌mol O2鈭檚-1鈭橪-1] or [nmol O2鈭檚-1鈭橪-1]
By definition the volume-specific oxygen flux is the advancement of reaction per volume of the reaction chamber.
Oxygen flux per mass (= mass-specific oxygen flux) is expressed in units [碌mol O2鈭檚-1鈭檏g-1] = [pmol O2鈭檚-1鈭檓g-1]
By definition the mass-specific oxygen flux is the advancement of reaction per mass of the sample enclosed in the reaction chamber.


Bioblast linkReferenceYear
Gnaiger E et al 鈥 MitoEAGLE Task Group (2020) Mitochondrial physiology. Bioenerg Commun 2020.1. https://doi.org/10.26124/bec:2020-0001.v12020


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MitoPedia concepts: MiP concept, Ergodynamics 

MitoPedia methods: Respirometry 

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