Analysis of signal amplitude in stopped-flow method for enzyme-ligand systems

Signal amplitudes of reaction curves obtainable by the stopped-flow method depend on the reaction mechanism as well as the optical properties of reactants, products and transient intermediates. Equation were derived for the concentration dependence of signal amplitudes expressed as absorbance changes for three typical reaction mechanisms which appear frequently in enzyme-ligand interactions. These relationships can be conveniently used to monitor experimentally observed signal amplitudes and characterize the optical properties of the transient intermediates. A useful method for accurately determining the dead-time of a stopped-flow apparatus is also described.