Step
|
State
|
Pathway
|
Q-junction
|
Comment - Events (E) and Marks (M)
|
1OctM
|
OctML(n)
|
F(N)
|
FAO
|
1OctM
- Respiratory stimulation of the FAO-pathway, F, by fatty acid, FA, in the presence of malate, M. Malate is a type N substrate (N), required for the F-pathway. The FA concentration has to be optimized to saturate the F-pathway, without inhibiting or uncoupling respiration. Low concentration of malate, typically 0.1 mM, does not saturate the N-pathway; but saturates the F-pathway. Non-phosphorylating resting state (LEAK state); LEAK respiration L(n) in the absence of ADP, ATP, AMP (no adenylates).
|
2D
|
OctMP
|
F(N)
|
FAO
|
1OctM;2D
- Respiratory stimulation of the FAO-pathway, F, by fatty acid, FA, in the presence of malate, M. Malate is a type N substrate (N), required for the F-pathway. The FA concentration has to be optimized to saturate the F-pathway, without inhibiting or uncoupling respiration. Low concentration of malate, typically 0.1 mM, does not saturate the N-pathway; but saturates the F-pathway. OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
|
2c
|
OctMcP
|
FN
|
FAO
|
1OctM;2D;2c
- NADH-linked substrates (type N-pathway to Q). Respiratory stimulation of the FAO-pathway, F, by fatty acid, FA, in the presence of malate, M. Malate is a type N substrate (N), required for the F-pathway. The FA concentration has to be optimized to saturate the F-pathway, without inhibiting or uncoupling respiration. OXPHOS capacity P (with saturating [ADP]), active OXPHOS state. Addition of cytochrome c yields a test for integrity of the mtOM (cytochrome c control efficiency). Stimulation by added cytochrome c would indicate an injury of the mtOM and limitation of respiration in the preceding state without added c due to loss of cytochrome c. Typically, cytochrome c is added immediately after the earliest ADP-activation step (OXPHOS capacity P with saturating [ADP]).
|
3G
|
OctGMP
|
FN
|
F&CI
|
1OctM;2D;2c;3G;
|
4S
|
OctGMSP
|
FNS
|
F&CI&II
|
1OctM;2D;2c;3G;4S
- Respiratory stimulation by simultaneous action of type N substrates & succinate, with convergent electron flow in the NS-pathway for reconstitution of TCA cycle function. Respiratory stimulation of the FAO-pathway, F, by fatty acid, FA, in the presence of malate, M. Malate is a type N substrate (N), required for the F-pathway. The FA concentration has to be optimized to saturate the F-pathway, without inhibiting or uncoupling respiration. OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
|
5U
|
OctGMSE
|
FNS
|
F&CI&II
|
1OctM;2D;2c;3G;4S;5U
- Respiratory stimulation by simultaneous action of type N substrates & succinate, with convergent electron flow in the NS-pathway for reconstitution of TCA cycle function. Respiratory stimulation of the FAO-pathway, F, by fatty acid, FA, in the presence of malate, M. Malate is a type N substrate (N), required for the F-pathway. The FA concentration has to be optimized to saturate the F-pathway, without inhibiting or uncoupling respiration. Noncoupled electron transfer state, ET state, with ET capacity E.
|
6Rot
|
SE
|
S
|
CII
|
1OctM;2D;2c;3G;4S;5U;6Rot
|
7Ama
|
ROX
|
|
|
1OctM;2D;2c;3G;4S;5U;6Rot;7Ama
- Rox is the residual oxygen consumption in the ROX state, due to oxidative side reactions, estimated either after inhibition of CIII (e.g. antimycin A, myxothiazol), CIV (e.g. Cyanide) or in the absence of endogenous fuel-substrates. Rox is subtracted from oxygen flux as a baseline for all respiratory states, to obtain mitochondrial respiration.
|