Molecular Weights of Proteins and Some Other Materials Including Sedimentation, Diffusion, and Frictional Coefficients and Partial Specific Volumes

These tables follow earlier compilations, notably by Svedberg and Pedersen [235] and Edsall [55], and are similarly concerned primarily with information relating to ultracentrifuge studies, particularly by the sedimentation velocity technique. Such studies require direct measurement of the sedimentation coefficient, S; diffusion coefficient, D; and partial specific volume, V. From these three values, it is possible to calculate the molecular weight, M, and the frictional coefficient, f/f ₀. The latter is a ratio expressing the resistance met with by the sedimenting molecule, relative to that of a smooth spherical particle of the same weight and density. It is generally assumed as a first approximation that increasing values indicate increasing axial ratios, that is, that there is departure from the spherical shape (f/f ₀ = 1) towards something more elongated (f/f ₀ > 1). However, the degree of hydration can also influence the frictional coefficient markedly.