Nonlinear control of regulatory enzymes

In highly complex metabolic systems, composed of interlocking and overlapping biosynthetic and degradative pathways, the control of certain strategic enzyme activities is more critical to the maintenance of fine balance between the various metabolic functions than is the control of others. The overall regulatory plan of such pathways depend largely on the nature of the biochemical reactions, the extent of branching as well as the physiological requirements of the given organism. It is now recognized that various different kinds of feedback control mechanisms have been evolved in order to accommodate the regulation of such divergent pathways; the specific control characteristics of regulatory enzymes determine the desired regulatory patterns.