... example of this phenomenon is offeredby an enzyme-catalyzed reaction where the function is the conversion of one metabolite into another: in thiscase, the formation and dispersion of the complex of the ... The concentrations of the molecules depicted in boxes are the state variables in the model [8],whereas the concentrations of the remaining molecules are modeled as constants. Molecular names containing ... denote the concentrations of S,P, E and C by s , p, e and c, respectively. We regard the total concentration of (free and bound) enzyme etot¼e + c as constant, based on the fact that changes on the...