Variation of sedimentation coefficient with rotor velocity.

The sedimentation coefficients of three proteins, which appeared homogeneous in the ultracentrifuge, have been determined at different rotor velocities. Two of the proteins, ovalbumin and human gamma-globulin, showed sedimentation coefficients that were approx. 10% higher at rotor velocities below 20000rev./min. than at 56100rev./min. The third protein, haemocyanin of Jasus lalandii, could not be investigated over the same rotor-velocity range, but it showed a similar effect.