Macromolecular crowding upon in-vivo-like enzyme-kinetics: effect of enzyme-obstacle size ratio

Abstract

In the present work, the volume exclusion phenomenon, also known as macromolecular crowding, has been applied to the field of enzyme kinetics. It has been approached by adding polymeric obstacles in the media of different enzymatic reactions. The concentration and size of these obstacles have been changed systematically in order to obtain kinetic information about each reaction. Results indicate that the performance of a certain enzyme always depends on the amount of excluded volume. However, only large, oligomeric proteins display an obstacle size-dependent behavior. Besides, crowding can hinder diffusion to the extent of being capable of shifting reaction control from activation to diffusion.