Substrate S is converted into product P through intermediates M1 and M2. The metabolic reactions are catalyzed by three enzymes, E1, E2, and E3. The expression of mRNAs G1, G2, and G3 is repressed by the metabolites M1, M2, and P, respectively. The proteins E1, E2, and E3 are translated from G1, G2, and G3, respectively. E1, E2, E3, G1, G2, and G3 degrade. The initial concentration of S is 1.
