Sedimentation equilibrium in macromolecular solutions of arbitrary concentration. I. Self-associating proteins

✍ Scribed by Ronald C. Chatelier; Allen P. Minton

• Publisher: Wiley (John Wiley & Sons)
• Year: 1987
• Tongue: English
• Weight: 972 KB
• Volume: 26
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360260405

✦ Synopsis

Synopsis

Relations describing sedimentation equilibrium in solutions of self-associating macromolecules at arbitrary concentration are presented. These relations are obtained by using scaled-particle theory to calculate the thermodynamic activity of each species present at a given radial distance. The results are expected to be valid for solutions of globular proteins under conditions such that interactions between individual solute molecules may be approximated by a hard-particle potential. Sedimentation equilibria in solutions containing either a n o n d a t i n g solute or a solute that self-associates according to several different schemes are simulated using the derived relations. The results of these simulations are presented in terms of the dependence of apparent weight-average molecular weight upon solute concentration. Simple empirical relations are presented for estimating the true weight-average molecular weight from the apparent weightaverage molecular weight, without reference to any particular self-association scheme. The weight-average molecular weight estimated in this fashion is within a few percent of the true weight-average molecular weight at all experimentally realizable solute concentrations (< 400 g/L).