Coupling-control ratio

high-resolution terminology - matching measurements at high-resolution

Coupling-control ratio

Description

Coupling-control ratios CCR are flux control ratios FCR at a constant mitochondrial pathway-control state. In mitochondrial preparations, there are three well-defined coupling states of respiration: LEAK respiration, OXPHOS, and Electron-transfer-pathway state (ET state). In these states, the corresponding respirtory rates are symbolized as L, P, and E. In living cells, the OXPHOS state cannot be induced, but in the ROUTINE state the respiration rate is R. A reference rate Z is defined by taking Z as the maximum flux, i.e. flux E in the ET-state, such that the lower and upper limits of the CCR are defined as 0.0 and 1.0. Then there are two mitochondrial CCR, L/E and P/E, and two CCR for living cells, L/E and R/E.

Abbreviation: CCR

Reference: Flux control ratio, Gnaiger 2020 BEC MitoPathways

References

Bioblast link	Reference	Year
Gnaiger 2020 BEC MitoPathways	Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5^th ed. Bioenerg Commun 2020.2. https://doi.org/10.26124/bec:2020-0002	2020
BEC 2020.1 doi10.26124bec2020-0001.v1	Gnaiger E et al ― MitoEAGLE Task Group (2020) Mitochondrial physiology. Bioenerg Commun 2020.1. https://doi.org/10.26124/bec:2020-0001.v1	2020

Keywords

```
The Blue Book 2020
```
OXPHOS-, ROUTINE-, ET-, and LEAK states; respiratory capacities (P, R, E, L) corrected for residual oxygen consumption Rox.
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 P» (ADP to ATP) without competing with P».
(P-L)/P is the OXPHOS P-L control efficiency. The biochemical coupling efficiency is independent of kinetic control by the phosphorylation system when expressed as the E-L coupling efficiency, (E-L)/E. (E-P)/E is the kinetic E-P control efficiency.

Bioblast links: Coupling control - >>>>>>> - Click on [Expand] or [Collapse] - >>>>>>>

1. Mitochondrial and cellular respiratory rates in coupling-control states

» Baseline state

Respiratory rate	Defining relations
OXPHOS capacity	P = P´-Rox	mt-preparations
ROUTINE respiration	R = R´-Rox	living cells
ET capacity	E = E´-Rox	» Level flow
		» Noncoupled respiration - Uncoupler
LEAK respiration	L = L´-Rox	» Static head
		» LEAK state with ATP
		» LEAK state with oligomycin
		» LEAK state without adenylates
Residual oxygen consumption Rox	L = L´-Rox

Chance and Williams nomenclature: respiratory states

» State 1 —» State 2 —» State 3 —» State 4 —» State 5

2. Flux control ratios related to coupling in mt-preparations and living cells

» Flux control ratio

» Coupling-control ratio

» Coupling-control protocol

FCR	Definition
L/P coupling-control ratio	L/P	» Respiratory acceptor control ratio, RCR = P/L
L/R coupling-control ratio	L/R
L/E coupling-control ratio	L/E	» Uncoupling-control ratio, UCR = E/L (ambiguous)
P/E control ratio	P/E
R/E control ratio	R/E	» 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

» Flux control efficiency j_Z-Y

» Background state

» Reference state

» Metabolic control variable

Coupling-control efficiency		Definition		Canonical term
P-L control efficiency	j_P-L	= (P-L)/P	= 1-L/P	P-L OXPHOS-flux control efficiency
R-L control efficiency	j_R-L	= (R-L)/R	= 1-L/R	R-L ROUTINE-flux control efficiency
E-L coupling efficiency	j_E-L	= (E-L)/E	= 1-L/E	E-L ET-coupling efficiency » Biochemical coupling efficiency
E-P control efficiency	j_E-P	= (E-P)/E	= 1-P/E	E-P ET-excess flux control efficiency
E-R control efficiency	j_E-R	= (E-R)/E	= 1-R/E	E-R ET-reserve flux control efficiency