Transcriptional control of metabolic fluxes

Abstract

Mol Syst Biol. 7: 478 Metabolism is at the core of cellular function, and it comprises thousands of reactions that are involved in the degradation of nutrients and biosynthesis of cellular constituents such as proteins, lipids, carbohydrates, DNA and RNA. These cellular constituents are macromolecules that are formed by polymerization of so‐called building blocks. Key building blocks are amino acids (for biosynthesis of proteins), fatty acids (for biosynthesis of lipids), nucleotides (for biosynthesis of RNA and DNA), and sugar moieties (for biosynthesis of carbohydrates). While there are more than 50 building blocks, it is fascinating that these are all formed from only 12 so‐called precursor metabolites (Nielsen, 2003). These 12 precursor metabolites are precursors for the formation of all organic chemicals found in nature, and hence the biosynthesis of these is remarkably conserved among all living organisms. They are formed from carbon and energy sources, e.g., glucose, fructose, and galactose, in what is generally referred to as the central carbon metabolism, which besides formation of the 12 precursor metabolites also ensures provision of Gibbs free energy, primarily in the form of ATP, and electron acceptors/donors, primarily in the form of NADH and NADPH, that are required for biosynthesis of building blocks and macromolecules. In order to ensure balanced provision of the 12 precursor metabolites, ATP, NADH, and NADPH for …