Quantitative assessment of the relative contributions of steric repulsion and chemical interactions to macromolecular crowding.
The term "macromolecular crowding" denotes the combined effects of high volume fractions of nominally unrelated macromolecules upon the equilibrium and transport properties of all macrosolutes, dilute as well as concentrated, in the crowded medium. We present a formal partitioning of the total crowding effect into contributions from steric exclusion (excluded volume) and weak, nonspecific attractive interactions between a concentrated "crowding agent" and reactant and product species present at trace concentration. A numerical example of the combined effect of both steric and chemical interactions between crowder and tracer upon the reversible dimerization of tracer is presented, based upon reasonable estimates of the magnitude of both repulsive and attractive interactions between tracer and crowder species.
Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD. minton@helix.nih.gov.
Allen P
AP
Minton
D019281:Dimerization; D046911:Macromolecular Substances / Q000737:chemistry
D046911:Macromolecular Substances