Optimal design of feedback control by inhibition

Summary

A recently developed, nonlinear method of systems analysis has been used to compare alternative patterns of control by feedback inhibition in otherwise equivalent unbranched biosynthetic pathways. The steady state performance of the simple case with end-product inhibition at the first physiologically important step is optimal with respect to the following criteria: the ability to (i) meet an increased demand for the end-product, (ii) meet this increased demand with limited accumulation of the intermediates, (iii) respond to an increased supply of the initial substrate, and (iv) limit the accumulation of the intermediates while responding to the increased availability of the initial substrate. The importance of these properties for the selection of feedback patterns in biosynthetic pathways is discussed.