Malate anaplerotic pathway control state

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Bioblasts - Richard Altmann and MiPArt by Odra Noel
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Malate anaplerotic pathway control state


M: Malate alone does not support respiration of mt-preparations if oxaloacetate cannot be metabolized further in the absence of a source of acetyl-CoA. Transport of oxaloacetate across the inner mt-membrane is restricted particularly in liver. Mitochondrial citrate and 2-oxoglutarate (α-ketoglutarate) are depleted by antiport with malate. Succinate is lost from the mitochondria through the dicarboxylate carrier. OXPHOS capacity with malate alone is only 1.3% of that with Pyruvate&Malate in isolated rat skeletal muscle mitochondria. Many mammalian and non-mammalian mitochondria have a mt-isoform of NADP+- or NAD(P)+-dependent malic enzyme (mtME), the latter being particularly active in proliferating cells. Then the anaplerotic pathway control state with malate alone (aN) supports high respiratory activities comparable to the NADH-linked pathway control states (N) with pyruvate&malate or glutamate&malate substrate combinations (PM pathway control state, GM pathway control state).

Abbreviation: M

Reference: Gnaiger 2014 MitoPathways - Chapter 3.1

MitoPedia concepts: SUIT state 

Communicated by Gnaiger E 2016-01-24, edited 2016-11-30.
M and malic enzyme