Template:SUIT-005

Steps and respiratory states

Step	State	Pathway	Q-junction	Comment - Events (E) and Marks (M)
1OctM	OctM_L	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	OctM_P	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	OctMc_P	F(N)	FAO	1OCtM;2D;2c 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. 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]). OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
3P	OctPM_P	FN	F&CI	1OctM;2D;2c;3P 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.
4S	OctPMS_P	FNS	F&CI&II	1OctM;2D;2c;3P;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	OctPMS_E	FNS	F&CI&II	1OctM;2D;2c;3P;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	S_E	S	CII	1OctM;2D;3P;4S;5U;6Rot Succinate pathway control state (S-pathway) after inhibiting CI with rotenone, which also inhibits the F-pathway. Noncoupled electron transfer state, ET state, with ET capacity E.
7Ama	ROX			1OctM;2D;3P;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.