Template:SUIT-011

Step	Respiratory state	Pathway control	ET-Complex entry into Q-junction	Comment
1GM	GML	N	CI	GML or GM_L: N-LEAK respiration, NL NADH-linked substrates glutamate & malate (type N; CI-linked pathway to Q). Non-phosphorylating resting state (LEAK state); Ln in the absence of ADP, ATP, AMP (no adenylates).
2D	GMP	N	CI	GMP or GM_P: N-OXPHOS capacity, NP OXPHOS capacity, P (with saturating [ADP]), with NADH-linked substrates glutamate&malate.
D(c)	GMcP	N	CI	GMcP or GMc_P: Cytochrome c test for quality control Addition of cytochrome c yields a test for integrity of the mtOM. Stimulation by added cytochrome c would indicate an injury of the mtOM and limitation of respiration in state GMP due to loss of cytochrome c (P, OXPHOS capacity with type N substrates). Cytochrome c is added immediately after the earliest ADP-activation step.
3S	GMSP	NS	CI&II	GMSP or GMS_P: NS-OXPHOS capacity, NSP Respiratory stimulation by further addition of succinate, S, to type N substrates, with convergent electron flow in the NS-pathway (CI&II-linked pathway to the Q-junction) for reconstitution of TCA cycle function, in the coupled state as an estimate of OXPHOS-capacity, P.
4U	GMSE	NS	CI&II	GMSE or GMS_E: NS-ET capacity, NSE Uncoupler titration (avoiding inhibition by high uncoupler concentrations) to obtain electron transfer (ET) capacity (noncoupled ET-state), as a test for limitation of OXPHOS-capacity by the phosphorylation system (ANT, ATP synthase, phosphate transporter) relative to ET-capacity, E.
5Rot	SE	S	CII	SE or S_E: S-ET capacity S-pathway ET-capacity after blocking CI with rotenone.
6Ama	ROX			ROX: residual oxygen consumption Rox is 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).