ME3:Mg2+ tetramer oxidatively decarboxylates MAL to PYR

Stable Identifier
R-HSA-9012349
Type
Reaction [transition]
Species
Homo sapiens
Compartment
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One hallmark of cancer is altered cellular metabolism. Malic enzymes (MEs) are a family of homotetrameric enzymes that catalyse the reversible oxidative decarboxylation of L-malate to pyruvate, with a simultaneous reduction of NAD(P)+ to NAD(P)H. As MEs generate NADPH and NADH, they may play roles in energy production and reductive biosynthesis. Humans possess three ME isoforms; ME1 is cytosolic and utilises NADP+, ME3 is mitochondrial and can utilise NADP+ and ME2 is mitochondrial and can utililse either NAD+ or NADP+ (Chang & Tong 2003, Murugan & Hung 2012).

NADP-dependent malic enzyme (ME3, aka m-NADP-ME) is a mitochondrial enzyme that oxidatively decarboxylates (s)-malate (MAL) to pyruvate (PYR) and CO2 using NADP+ as cofactor (Loeber et al. 1994). ME1 exists as a dimer of dimers (Murugan & Hung 2012) and a divalent metal such as Mg2+ is essential for catalysis (Chang & Tong 2003). ME3 may play a role in insulin secretion (Hasan et al. 2015) but how it does this in panceratic beta cells has not been established yet.

Literature References
PubMed ID Title Journal Year
7818469 Purification, cDNA cloning and heterologous expression of the human mitochondrial NADP(+)-dependent malic enzyme

Loeber, G, Maurer-Fogy, I, Schwendenwein, R

Biochem. J. 1994
Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
malate dehydrogenase (decarboxylating) (NADP+) activity of ME3:Mg2+ tetramer [mitochondrial matrix]
Physical Entity
Activity
Orthologous Events
Cross References
Rhea
Authored
Reviewed
Created