Template:SUIT-006

Steps and respiratory states

Step	State	Comment - Events (E) and Marks (M)
1X	L	1X X: combination of substrates and inhibitors chosen according to the aims. Non-phosphorylating resting state (LEAK state); LEAK respiration L(n) in the absence of ADP, ATP, AMP (no adenylates).
2D	P	1X;2D OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
3(Omy)	L	1X;2D;3Omy Non-phosphorylating resting state (LEAK state); LEAK-respiration, L(Omy), after blocking the ATP synthase with oligomycin. The addition of oligomycin or its carrier is optional depending on the experimental question to resolve.
4U	E	1X;2D;3Omy;4U Uncoupler titration (avoiding inhibition by high uncoupler concentrations) to obtain electron transfer (ET) capacity E (noncoupled ET-state). Test for limitation of OXPHOS capacity P by the phosphorylation system (ANT, ATP synthase, phosphate transporter) relative to ET capacity E in mt-preparations: E-P control efficiency and E-L coupling efficiency. In living cells: E-R control efficiency and E-L coupling efficiency.
4Ama	ROX	Rox is the residual oxygen consumption in the ROX state, due to oxidative side reactions, estimated after addition of antimycin A (inhibitor of CIII). Rox is subtracted from oxygen flux as a baseline for all respiratory states, to obtain mitochondrial respiration (mt).