Respiratory state

high-resolution terminology - matching measurements at high-resolution

Respiratory state

Description

Respiratory states of mitochondrial preparations and living cells are defined in the current literature in many ways and with a diversity of terms. Mitochondrial respiratory states must be defined in terms of both, the coupling-control state and the electron-transfer-pathway state.

Reference: Gnaiger 2020 MitoPathways

Communicated by Gnaiger E 2010-10-21, edited 2016-08-26. Edited by Doerrier C 2020-04-23.

Coupling control states

Coupling control states and CCR of mitochondrial preparations:

• OXPHOS, LEAK respiration, ET-pathway (P, L, E) - corrected for ROX. CCR: L/E, P/E, L/P

Coupling control states of living cells:

• ROUTINE, LEAK respiration, ET-pathway (R, L, E) - corrected for ROX. CCR: L/E, R/E, L/R

Electron-transfer-pathway state

Electron-transfer-pathway state, are defined by substrate type (at saturating concentration):

• Living cells: endogenous, exogenous substrate control
• Mitochondrial preparations: specific substrate-inhibitor combinations for selectively stimulating electron entry through Complex I (NADH pathway), CII (succinate pathway), or other branches converging at the Q-junction, particularly with fatty acid oxidation (fatty acid oxidation pathway control state), alpha-glycerophosphate, or substrate combinations applied for reconstitution of TCA cycle function (e.g. NS-pathway control state, etc.).

Control by substrate concentration: Kinetic control states:

• Kinetic substrate or adenylate control: Kinetic studies with variation of a specific substrate (reduced substrate supplying electrons to the ETS; ADP, Pi; O₂; cytochrome c) are analyzed by kinetic functions (e.g. hyperbolic), yielding apparent kinetic constants, such as J_max, K_m', c₅₀, or p₅₀.
• Kinetic inhibitor control: Kinetic studies with variation of a specific inhibitor yield apparent kinetic constants, such as the K_I'.

Classical respiratory states

Chance and Williams (1955):

• State 1, State 2, State 3, State 4, State 5. CCR: RCR

Derived respiratory states:

• State 3u, State 4o. CCR: UCR

Thermodynamics of irreversible processes:

• Static head, Level flow

MitoPedia: Respiratory states

» See the complete MitoPedia: Respiratory states

» MitoPedia: SUIT

MitoPedia concepts: MiP concept, Respiratory state, SUIT concept, Recommended 

MitoPedia methods: Respirometry, Spectrophotometry 

MitoPedia topics: EAGLE