Sensitivity amplification in biochemical systems

Abstract

The sensitivity of biological systems to changes in environmental stimuli is connected with their regulatory properties. In order to achieve efficient control, these systems must respond to minute environmental variations by amplifying external stimuli to yield a significant response. To that end, biochemical systems have often evolved to a cascade organization in which the product of the nth reaction in a chain acts as a catalyst in subsequent transformations. The amplification properties of such cascades were first noticed in the process of blood clotting (MacFarlane, 1964, 1969) and visual excitation (Wald, 1965). Later on, a similar organization was noticed in hormonal control of metabolism (Bowness, 1964; Stadtman & Chock, 1977, 1978; Chock, Rhee & Stadtman, 1980).