Effects of product inhibition in metabolic pathways: stability and control

The effect of product inhibition in metabolic pathways is examined using (a) an unbranched pathway in the absence of endproduct inhibition and (b) an unbranched pathway with endproduct inhibition. It is shown that product inhibition may be considered an alternative mechanism to endproduct inhibition for reducing the overall logarithmic gain of an unregulated pathway. When product inhibition and endproduct inhibition are both present, they act in concert with each other to lower the overall logarithmic gain and alleviate parameter sensitivities. Product inhibition is also found to exert a stabilizing influence that competes with the destabilizing effect of endproduct inhibition in controlling the dynamic behavior.