“…Development of computational methods for 13 C-based flux analysis has, therefore, focused on speeding up the calculation of amino acid/metabolite labeling from an assumed set of fluxes. Several methods have been proposed, including the iterative averaging isotopomer method (Schmidt, Nielsen, & Villadsen, 1999a), the cumomer method (Wiechert et al, 1999), the Elementary Metabolic Unit (EMU) method (Antoniewicz, Kelleher, & Stephanopoulos, 2007b), the isotopomer path tracing method (Forbes, Clark, & Blanch, 2001), and the fractional labeling method (Riascos, Gombert, & Pinto, 2005). In practice, the only methods under continuous development are the cumomer and EMU method.…”