Template:SUIT-031 Q mt D072

Steps and respiratory states

Step	State	Pathway	Q-junction	Comment - Events (E) and Marks (M)
1Q				1Q To detect the redox state of the Q-pool a mimetic coenzyme Q2 is applied in suspension, which reacts both with the detecting electrode and the biological sites (CI, CII and CIII).
1PM	PML(n)	N	CI	1PM NADH-linked substrates (type N-pathway to Q). Non-phosphorylating resting state (LEAK state); LEAK respiration L(n) in the absence of ADP, ATP, AMP (no adenylates).
2D	PMP	N	CI	1PM;2D NADH-linked substrates (type N-pathway to Q). OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
3S	PMSP	NS	CI&II	1PM;2D;3S Respiratory stimulation by simultaneous action of type N substrates & succinate, with convergent electron flow in the NS-pathway for reconstitution of TCA cycle function. OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
4Rot	SP	S	CII	1PM;2D;3S;4Rot Succinate pathway control state (S-pathway) after inhibiting CI with rotenone, which also inhibits the F-pathway. OXPHOS capacity P (with saturating [ADP]), active OXPHOS state.
5U	SE	N	CII	1PM;2D;3S;4Rot;5U Succinate, S ( type S-pathway to Q). 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. Noncoupled electron transfer state, ET state, with ET capacity E.
6Anoxia				1PM;2D;3S;4Rot;5U;6Anoxia Anoxia is a crucial step to detect the fully reduced Q-junction in the presence of coenzyme Q2 after the biological sample has consumed the O2 in the O2k-chamber for calculation of the Q redox state.
7Ama	ROX			1PM;2D;3S;4Rot;5U;6Anoxia;7Ama 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).

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Coupling control

» Coupling control state

» ET capacity

» OXPHOS capacity

» LEAK respiration

Pathway control

» Electron transfer pathway

» Fatty acid oxidation pathway control state, F

» NADH electron transfer-pathway state, N

» Succinate pathway control state, S

» NS-pathway control state, NS

» Glycerophosphate pathway control state, Gp

» Complex IV single step, CIV

» Anaplerotic pathway control state

Main fuel substrates

» Glutamate, G

» Glycerophosphate, Gp

» Malate, M

» Octanoylcarnitine, Oct

» Pyruvate, P

» Succinate, S

Glossary

» List of SUIT states

» SUIT concept