Determination of oligomeric states is an important issue in protein chemistry. For example, self-assembly via oligomerization domains is crucial for the regulation of several protein kinases. Determination of the oligomeric state of fragments of these kinases is a means of verifying the involvement of each domain in self-assembly.
Analytical size exclusion chromatography (SEC) is widely used for determining molar mass and oligomeric state of proteins in solution, but it exhibits some important limitations. For example, interactions of proteins with column material can lead to delayed elution and hence erroneous results when relying on column calibration. Since even ideal elution occurs according to hydrodynamic size rather than true molecular weight, there are no appropriate molar mass gel filtration standards for analysis of proteins, fragments or complexes of non-globular structure that present a different size/molecular weight dependence than globular proteins.
