If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Locations of Mapped Genes:
|Superclasses:||Degradation/Utilization/Assimilation → Carboxylates Degradation|
Under aerobic conditions, E. coli is able to utilize D-malate as the sole source of carbon for growth. D-malate is transported into the cell by the proton motive force-dependend dicarboxylate transporter DctA. A D-malate-specific enzyme, D-malate / 3-isopropylmalate dehydrogenase (decarboxylating), decarboxylates D-malate to pyruvate while reducing NAD+. Pyruvate then enters central metabolism via pyruvate dehydrogenase. [Stern66, Reed06, Lukas10]
Under anaerobic conditions, fermentation of pyruvate via pyruvate-formate lyase and the pathway of mixed acid fermentation is theoretically feasible, but that route does not produce enough ATP to compensate for the loss of ATP by utilization of the proton motive force during D-malate transport. Thus, D-malate alone is unable to support growth as the sole source of carbon under anaerobic conditions [Lukas10].
Lukas10: Lukas H, Reimann J, Kim OB, Grimpo J, Unden G (2010). "The regulation of aerobic and anaerobic D-malate metabolism of Escherichia coli by the LysR-type regulator DmlR (former YeaT)." J Bacteriol 192(10):2503-11. PMID: 20233924
Reed06: Reed JL, Patel TR, Chen KH, Joyce AR, Applebee MK, Herring CD, Bui OT, Knight EM, Fong SS, Palsson BO (2006). "Systems approach to refining genome annotation." Proc Natl Acad Sci U S A 103(46);17480-4. PMID: 17088549
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
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