Metabolomics of central carbon metabolism in Mycobacterium tuberculosis

Central carbon metabolism (CCM)-defined as the enzymatic transformation of carbon through glycolysis, the pentose phosphate pathway (PPP), the citric acid cycle, the glyoxylate shunt, the methylcitrate cycle, and gluconeogenesis-is a core feature of all cells that is used to provide energy, in the form of reducing equivalents and ATP, and essential biosynthetic precursors (Fig. 1). Remarkably, the same metabolic enzymes found in bacteria are also present in mammals, suggesting that the pathways of CCM have been fundamentally conserved. Intensive study has thus focused on the metabolic network of Escherichia coli as a model system with which to understand its basic principles. However, cells vary in their specific metabolic needs according to the selective pressures they encounter. Accordingly, growing evidence has established that metabolic enzymes are often capable of operating in a diverse array of configurations (1).