Upon centrifugation, particles sediment at different rates due to their physical properties. Tropomyosin is a rod-shaped protein
with a mass of 70 kDa and a sedimentation coefficient of 2.6S. Hemoglobin is a spherical protein with a slightly smaller mass of 65 kDa, but a much higher sedimentation coefficient of 4.31S. Which property of tropomyosin accounts for its slow sedimentation?
Centrifugation separates molecules on the basis of angular motion.
Due to spherical shape, the value of 'f' is lesser for a spherical protien than the rod shaped one.
Hence the sedimentation coefficient for an elongated protien is 2.6S while htat of a spherical protien is 4.31S.
Hence its elongated shape results in slow centrifugation.
Some of the important principles of centrifugation are as follows :
The greater the mass, the more is the sedimentation rate i-e the one with greater mass will move down more rapidly as compared to the one with les mass.
Shape of particles also effect it, the rounder the particle, the lower frictional coeeficient.
