P-L net OXPHOS capacity

high-resolution terminology - matching measurements at high-resolution

P-L net OXPHOS capacity

Description

The free OXPHOS capacity, ≈P, is the OXPHOS capacity corrected for LEAK respiration, ≈P = P-L. ≈P 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 the free OXPHOS capacity, ≈P, strictly coupled to phosphorylation, ~P, and nonphosphorylating LEAK respiration, L_P, compensating for proton leaks, slip and cation cycling: P = ≈P+L_P. It is frequently assumed that LEAK respiration, L, as measured in the LEAK state, overestimates the LEAK component of respiration, L_P, as measured in the OXPHOS state, particularly if the protonmotive force is not adjusted to equivalent levels in L and L_P. However, if the LEAK component increases with enzyme turnover during P, the low enzyme turnover during L may counteract the effect of the higher Δp_mt.

Abbreviation: ≈P

Reference: Gnaiger 2014 MitoPathways

MitoPedia methods: Respirometry 

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. 

The Blue Book 2014: Fig. 2.4.

Coupling control states for ≈P

» Respiratory state

• Reference state, Z_X: OXPHOS capacity, P = P´-ROX
• Background state, Y_X: LEAK respiration, L = L´-ROX
• Metabolic control variable, X=Z_X-Y_X: Scope of ADP stimulation, free OXPHOS capacity, ≈P = P-L

Flux control factor

» Flux control factor, FCF

• Coupling control factor, 1-Y_X/Z_X: P-L coupling control factor, OXPHOS coupling efficiency: j_≈P = ≈P/P =(P-L)/P = 1-L/P

Compare

Free ETS capacity, ≈E = E-L

netOXPHOS control ratio, ≈P/E control ratio: ≈P/E = (P-L)/E

ETS coupling efficiency, E-L control factor: j_≈E = ≈E/E = (E-L)/E = 1-L/E

• Intact cells: Free ROUTINE activity, ≈R = R-L