Analysis of the Reversible Aggregation of Macromolecules in a Centrifugal Field

Abstract

Solutions of macromolecules which associate in a non-specific manner to give indefinitely large aggregates can be expected to give characteristic patterns when examined by analytical ultracentrifuge. When the rate of reaction is slow, the different aggregates will behave as separate species, and, with Schlieren optics, will generally show separate peaks. When the rate of reaction is rapid, a complex peak will be shown, which has a general resemblance to that shown by dimerization. Aggregation can also occur as a background to a single strong polymerization, giving a pattern which can be confused with those shown by certain other associating systems. Methods for recognizing aggregation, and for obtaining quantitative data, from these patterns are discussed.