Control analysis of transition times in metabolic systems

Abstract

The transition time, .tau., of a metabolic system is defined as the ratio of the metabolite concentrations in the system, .sigma., to the steady-state flux, J. Its value reflects a temporal characteristic of the system as it relaxes towards in the steady state. Like other systemic properties, the value of .tau. will be a function of the enzyme activities in the system. The influence of a particular enzyme activity of .tau. can be quantified by a Control Coefficient, Cei.tau.. We show that it is possible to derive a Summation Theorem .sum.i=1n Cei.tau. = -1 and a Connectivity Theorem .sum.i=1n Cei.tau. .cntdot. .epsilon.Skvi = -Sk/.sigma.. We establish a ''sign rule'' that predicts the order of positive and negative Control Coefficients in a sequence.