Examples of kcat values from BRENDA and the minimal values required to produce the reaction fluxes measured in 13C fluxomics experiments.

The minimal kcat is obtained by dividing 13C fluxes by mean protein counts using the Gene-Protein-Reaction (GPR) rules. The final kcat is obtained by the doubling procedure to reproduce a mean growth rate of 0.35 hr−1, and the final values of the associated mean vmax values obtained by taking mean vmax over 1000 cells from a population. Factor of 3.0 × 10−7 converts the units from cell−1 s−1 to mmol gDwt−1 hr−1. When more than one enzyme is responsible for a reaction, the GPR rules are used to determine how to process protein counts (sum of subunits in case of ‘or’ and minimum count among the subunits for ‘and’).