MOLECULAR BUREAUCRACY - WHO CONTROLS THE DELAYS - TRANSIENT TIMES IN BRANCHED PATHWAYS AND THEIR CONTROL

Analysis of metabolic control has until now been mainly confined to sy stems at steady state. This includes studies of the control of ''trans ition time'', which is actually a steady-state transit time that does not refer to the transient state. In this paper we examine the control of the transition state of a metabolic pathway in the approach to a s table steady state, showing that the time needed to attain it can be d ecreased or increased in different branches. Our analysis only applies to branched pathways, and we discuss why similar deviations cannot oc cur in unbranched pathways. In systems with several branches the accel eration of some branches during the transient phase, so that they reac h their steady states more quickly, occurs at the expense of others, w hich are thus delayed. We present theorems that describe properties of the transient variables and their control. (C) 1996 Academic Press Li mited