Could you please explain the Svedbergs equation (Lecture #5)?
The Svedberg unit is defined as V/w2r, where w2 is the square of the angular velocity (e.g., ~rpms), r is the distance from the center of rotation and V is the constant velocity at which the particle is sedimenting. This value will be higher for larger (higher MW) proteins. So a protein that yields an S value of 200 x 10^-13 sec will be much larger than a protein with an S value of 20 x 10^-13 sec. A Svedberg unit is defined as 10^-13 sec, so a protein's sedimentation behavior can be more conveniently referred to as 200S or 20S. The sedimentation will also be influenced by shape if the protein is not roughly spherical: S = M/fo where fo is the frictional coefficient and M is the molecular weight. This is all more than you need to know about Svedbergs. Just remember that a high S value means rapid sedimentation and a low S value means slow sedimentation and the rate of sedimentation is proportional to the MW and inversely proportional to the coefficient of friction.