Figure 1.

Process diagram of the biosynthesis of valine and leucine in C. glutamicum. The pathway shown here is constructed using the information from both the KEGG and the METACYC databases. Metabolites outside the cell are not directly included in the model system. As 2-ketoisovalerate (KIV) is the starting point for both products, its production and degradation are highly regulated. For this purpose four feedback inhibitions control the reactions linked to this intermediate. Val and Leu can be transported out of the cell when not needed thereby competing for a free binding site in the transporting enzyme. Note that enzymes are omitted from this process diagram for the sake of a clear arrangement of the participating species.