PM-pathway control state

high-resolution terminology - matching measurements at high-resolution

PM-pathway control state

Description

MitoPathway control state: NADH Electron transfer-pathway state

SUIT protocol: 1PM;2D;3U;4G;5S;6Oct;7Rot;8Gp- - SUIT_RP1

Pyruvate (P) is oxidatively decarboxylated to acetyl-CoA and CO₂, yielding NADH catalyzed by pyruvate dehydrogenase. Malate (M) is oxidized to oxaloacetate by mt-malate dehydrogenase located in the mitochondrial matrix. Condensation of oxaloacate with acetyl-CoA yields citrate (citrate synthase). 2-oxoglutarate (α-ketoglutarate) is formed from isocitrate (isocitrate dehydrogenase).

Abbreviation: PM

Reference: Gnaiger 2020 BEC MitoPathways

MitoPedia concepts: SUIT state

PM_L

LEAK state (L) with PM as N-linked substrates can be evaluated in the following SUIT protocols:

SUIT-001

DL-Protocol for isolated mitochondria and tissue homogenate (mt): SUIT-001 O2 mt D001
DL-Protocol for permeabilized fibers (pfi): SUIT-001 O2 pfi D002
DL-Protocol for permeabilized cells (pce): SUIT-001 O2 ce-pce D003
DL-Protocol for permeabilized blood cells (PBMC and PLT): SUIT-001 O2 ce-pce D004

SUIT-004

DL-Protocol for permeabilized fibers (pfi): SUIT-004 O2 pfi D010

SUIT-006

DL-Protocol for permeabilized cells (pce): SUIT-006 O2 ce-pce D029
DL-Protocol for isolated mitochondria and tissue homogenate (mt): SUIT-006 O2 mt D047

SUIT-008

DL-Protocol for permeabilized fibers (pfi): SUIT-008 O2 pfi D014

PM_P

OXPHOS state (P) with PM as N-linked substrates can be evaluated in the following SUIT protocols:

SUIT-001

DL-Protocol for isolated mitochondria and tissue homogenate (mt): SUIT-001 O2 mt D001
DL-Protocol for permeabilized fibers (pfi): SUIT-001 O2 pfi D002
DL-Protocol for permeabilized cells (pce): SUIT-001 O2 ce-pce D003
DL-Protocol for permeabilized blood cells (PBMC and PLT): SUIT-001 O2 ce-pce D004

SUIT-004

DL-Protocol for permeabilized fibers (pfi): SUIT-004 O2 pfi D010

SUIT-006

DL-Protocol for permeabilized cells (pce): SUIT-006 O2 ce-pce D029
DL-Protocol for isolated mitochondria and tissue homogenate (mt): SUIT-006 O2 mt D047

SUIT-008

DL-Protocol for permeabilized fibers (pfi): SUIT-008 O2 pfi D014

PM_E

ET state (E) with PM as N-linked substrates can be evaluated in the following SUIT protocols:

SUIT-001

DL-Protocol for isolated mitochondria and tissue homogenate (mt): SUIT-001 O2 mt D001
DL-Protocol for permeabilized fibers (pfi): SUIT-001 O2 pfi D002
DL-Protocol for permeabilized cells (pce): SUIT-001 O2 ce-pce D003
DL-Protocol for permeabilized blood cells (PBMC and PLT): SUIT-001 O2 ce-pce D004

SUIT-004

DL-Protocol for permeabilized fibers (pfi): SUIT-004 O2 pfi D010

SUIT-006

DL-Protocol for permeabilized cells (pce): SUIT-006 O2 ce-pce D029
DL-Protocol for isolated mitochondria and tissue homogenate (mt): SUIT-006 O2 mt D047

SUIT-008

DL-Protocol for permeabilized fibers (pfi): SUIT-008 O2 pfi D014

Linear coupling control in the N-pathway control state: L – P - E

L - P

OXPHOS-coupling efficiency (P-L or ≈P control factor), j_≈P = ≈P/P = (P-L)/P = 1-L/P, is measured in the N-linked pathway state, with defined coupling sites (CI, CIII, CIV) and at high flux.

P - E

CCCP is titrated stepwise to maximum flux, to evaluate limitation of OXPHOS by the phosphorylation system, expressed as the apparent excess E-P capacity factor (E-P coupling control factor), j_ExP = (E-P)/E = 1-P/E. If j_ExP>0, then the E-L coupling efficiency rather than the OXPHOS-coupling efficiency is the proper expression of coupling, j_≈E = ≈E/E = (E-L)/E = 1-L/E.

Discussion

The Pyruvate anaplerotic pathway control state (pyruvate alone) is not an ET-pathway competent substrate state in most mt-preparations, since acetyl-CoA accumulates without the co-substrate (oxaloacetate) of citrate synthase.

The Malate-anaplerotic pathway control state (M alone) is not an ET-pathway competent substrate state in many mt-preparations, since oxaloacetate accumulates without the co-substrate (acetyl-CoA) of citrate synthase.