- high-resolution terminology - matching measurements at high-resolution
State 4
Description
State 4 is the respiratory state obtained in isolated mitochondria after State 3, when added ADP is phosphorylated completely to ATP driven by electron transfer from defined respiratory substrates to O2 (Chance and Williams, 1955). State 4 represents LEAK respiration, LT (L for LEAK; T for ATP), or an overestimation of LEAK respiration if ATPase activity prevents final accumulation of ATP and maintains a continuous stimulation of respiration by recycled ADP. As is the case in all LEAK states (states of non-phosphorylating resting respiration; static head), the mt-membrane potential is increased to a maximum for a specific substrate or substrate combination.
Abbreviation: LT
Reference: Chance 1955 JBC-III, Gnaiger_2009_IJBCB, MiPNet12.15
Labels:
Preparation: Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.
Regulation: Respiration; OXPHOS; ETS Capacity"Respiration; OXPHOS; ETS Capacity" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property., Coupling; Membrane Potential"Coupling; Membrane Potential" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
Other uses
- State 4 is fundamentally different from State 2 (Chance and Williams, 1955), but unfortunately the latter has been misunderstood and re-defined to be comparable with State 4: ‘.. the controlled respiration prior to addition of ADP, which is strictly termed “state 2”, is functionally the same as state 4, and the latter term is usually used for both states’ (Nicholls and Ferguson 1992). The comparable states are not State 4 and State 2, but the LEAK state in the presence of ATP (State 4; LT) and in the absence of ATP and other adenylates (LN; N for no adenylates).
- State 4 yields identical respiratory flux as State 4o (Lo), if inhibition of ATP synthase by oligomycin (4o) is without effect compared to LT or LN.
