Question

Consider the two proteins A and B. Protein A has a MW = 75kDa and protein B has a MW = 15kDa. Which protein will sediment faster during rate zonal centrifugation? Which protein will migrate faster during SDS polyacrilamide gel electrophoresis?

Answer 1

In zonal centrifugation the protein having higher molecular mass sediments faster. So, in zonal centrifugation protein A will sediment faster as the molecular weight of protein A is greater than protein B. In SDS PAGE, the smaller protein that is protein B having 15 kDa molecular mass will migrate faster because SDS page has pores and the smaller the protein the easier is the movement for them. Larger protein have a hard time to go through the gel by squeezing between the pores.