Description
The P-L net OXPHOS capacity is the OXPHOS capacity corrected for LEAK respiration. P-L is the scope for ADP stimulation, the respiratory capacity potentially available for phosphorylation of ADP to ATP. Oxygen consumption in the OXPHOS state, therefore, is partitioned into P-L, strictly coupled to phosphorylation Pยป, and nonphosphorylating LEAK respiration, LP, compensating for proton leaks, slip and cation cycling: P = P-L+LP. It is frequently assumed that LEAK respiration L as measured in the LEAK state, overestimates the LEAK component of respiration, LP, as measured in the OXPHOS state, particularly if the protonmotive force is not adjusted to equivalent levels in L and LP. However, if the LEAK component increases with enzyme turnover during P, the low enzyme turnover during L may counteract the effect of the higher pmF.
Abbreviation: P-L
Reference: Gnaiger 2020 BEC MitoPathways
Communicated by Gnaiger E (2014-08-09) last update 2020-11-11
Keywords
- Expand Bioblast links to P-L net OXPHOS capacity
4-compartmental OXPHOS model. (1) ET capacity E of the noncoupled electron transfer system ETS. OXPHOS capacity P is partitioned into (2) the dissipative LEAK component L, and (3) ADP-stimulated P-L net OXPHOS capacity. (4) If P-L is kinetically limited by a low capacity of the phosphorylation system to utilize the protonmotive force pmF, then the apparent E-P excess capacity is available to drive coupled processes other than phosphorylation Pยป (ADP to ATP) without competing with Pยป.
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1. Mitochondrial and cellular respiratory rates in coupling-control states
Respiratory rate | Defining relations | Icon | |
---|---|---|---|
OXPHOS capacity | P = Pยด-Rox | mt-preparations | |
ROUTINE respiration | R = Rยด-Rox | living cells | |
ET capacity | E = Eยด-Rox | ยป Level flow | |
ยป Noncoupled respiration - Uncoupler | |||
LEAK respiration | L = Lยด-Rox | ยป Static head | |
ยป LEAK state with ATP | |||
ยป LEAK state with oligomycin | |||
ยป LEAK state without adenylates | |||
Residual oxygen consumption Rox | L = Lยด-Rox |
2. Flux control ratios related to coupling in mt-preparations and living cells
FCR | Definition | Icon | |
---|---|---|---|
L/P coupling-control ratio | L/P | ยป Respiratory acceptor control ratio, RCR = P/L | |
L/R coupling-control ratio | L/R | ||
L/E coupling-control ratio | L/E | ยป Uncoupling-control ratio, UCR = E/L (ambiguous) | |
P/E control ratio | P/E | ||
R/E control ratio | R/E | ยป Uncoupling-control ratio, UCR = E/L | |
net P/E control ratio | (P-L)/E | ||
net R/E control ratio | (R-L)/E |
3. Net, excess, and reserve capacities of respiration
Respiratory net rate | Definition | Icon |
---|---|---|
P-L net OXPHOS capacity | P-L | |
R-L net ROUTINE capacity | R-L | |
E-L net ET capacity | E-L | |
E-P excess capacity | E-P | |
E-R reserve capacity | E-R |
4. Flux control efficiencies related to coupling-control ratios
- ยป Flux control efficiency jZ-Y
- ยป Background state
- ยป Reference state
- ยป Metabolic control variable
Coupling-control efficiency | Definition | Icon | Canonical term | ||
---|---|---|---|---|---|
P-L control efficiency | jP-L | = (P-L)/P | = 1-L/P | P-L OXPHOS-flux control efficiency | |
R-L control efficiency | jR-L | = (R-L)/R | = 1-L/R | R-L ROUTINE-flux control efficiency | |
E-L coupling efficiency | jE-L | = (E-L)/E | = 1-L/E | E-L ET-coupling efficiency ยป Biochemical coupling efficiency | |
E-P control efficiency | jE-P | = (E-P)/E | = 1-P/E | E-P ET-excess flux control efficiency | |
E-R control efficiency | jE-R | = (E-R)/E | = 1-R/E | E-R ET-reserve flux control efficiency |
5. General
- ยป Basal respiration
- ยป Cell ergometry
- ยป Dyscoupled respiration
- ยป Dyscoupling
- ยป Electron leak
- ยป Electron-transfer-pathway state
- ยป Hyphenation
- ยป Oxidative phosphorylation
- ยป Oxygen flow
- ยป Oxygen flux
- ยป Permeabilized cells
- ยป Phosphorylation system
- ยป Proton leak
- ยป Proton slip
- ยป Respiratory state
- ยป Uncoupling