The intracellular environment is crowded. Macromolecules can occupy 30% of the cellular volume with their concentrations reaching 300 grams per Litre. In confined or crowded environments, the rates of biochemical reactions can differ markedly from their dilute, well-mixed counterparts. Crowding reduces the diffusion coefficient of reactants, slowing diffusion-limited reactions and giving rise to fractal-like reaction kinetics. Cellular crowded environments differ from concentrated environments in that crowded environments may have high molecular diversity. This means that although the volume fraction of solute molecules is high, the concentration of a specific species can be quite low.
It has been suggested that macromolecular crowding plays a role in cellular compartmentalization and phase separation. We are just beginning to understand the biophysical chemistry and kinetics of reactions inside cellular crowded environments. In our research group, we are interested in answering a number of interesting questions in this area. How does macromolecular crowding affects cellular physiology? Do we need to revise current theories for origin of cells and life taking into account the macromolecular organization of cells?