The use of high-performance liquid chromatography for the determination of size and molecular weight of proteins: a caution and a list of membrane proteins suitable as standards.

We propose a list of 15 water-soluble globular proteins and 13 forms of detergent-soluble membrane proteins of known Stokes radii for the calibration of high-performance liquid chromatography columns. It is shown that it is advisable to use different sets of standards for these two types of proteins as the detergent-solubilized membrane proteins may behave differently, being excluded or retarded, depending upon the gel support. A smooth, although nonlinear, relationship between Stokes radii and erf-1(1--KD) is observed while a large scatter of points exists if the calibration is expressed as the molecular weight as a function of KD.