This entry represents the NAD-binding domain of malic enzymes.

Malic enzymes (malate oxidoreductases) catalyse the oxidative decarboxylation of malate to form pyruvate, a reaction important in a number of metabolic pathways - e.g. carbon dioxide released from the reaction may be used in sugar production during the Calvin cycle of photosynthesis [ PUBMED:8300616 … expand

This entry represents the NAD-binding domain of malic enzymes.

Malic enzymes (malate oxidoreductases) catalyse the oxidative decarboxylation of malate to form pyruvate, a reaction important in a number of metabolic pathways - e.g. carbon dioxide released from the reaction may be used in sugar production during the Calvin cycle of photosynthesis [ PUBMED:8300616 ]. There are 3 forms of the enzyme [ PUBMED:1993674 ]: an NAD-dependent form that decarboxylates oxaloacetate; an NAD-dependent form that does not decarboxylate oxalo-acetate; and an NADPH-dependent form [ PUBMED:8300616 ]. Other proteins known to be similar to malic enzymes are the Escherichia coli scfA protein; an enzyme from Zea mays (Maize), formerly thought to be cinnamyl-alcohol dehydrogenase [ PUBMED:2103472 ]; and the hypothetical Saccharomyces cerevisiae protein YKL029c.

Studies on the duck liver malic enzyme reveals that it can be alkylated by bromopyruvate, resulting in the loss of oxidative decarboxylation and the subsequent enhancement of pyruvate reductase activity [ PUBMED:1911848 ]. The alkylated form is able to bind NADPH but not L-malate, indicating impaired substrate or divalent metal ion-binding in the active site [ PUBMED:1911848 ]. Sequence analysis has highlighted a cysteine residue as the point of alkylation, suggesting that it may play an important role in the activity of the enzyme [ PUBMED:1911848 ], although it is absent in the sequences from some species.

Malic enzyme is a tetramer comprised of subunits with four domains each [ PUBMED:10477256 PUBMED:12033925 PUBMED:1640469 ].