differential/isopycnic/rate zonal centrifugation

[jones106]

Hey guys, i'm a little confused about these types of centrifugation. Here is what I know (or think I know) about them:
Differential centrifugation is a good way to roughly separate cellular components based on their sedimentation coefficient (which is based on mass and shape). Larger and more massive components will sediment at lower speeds, while smaller components require higher centrifugal force.
Isopycnic uses a gradient of CsCl to separate based on buoyant densities. More dense components will equilibrate in the more dense regions of the CsCl while the less dense components will equilibrate in the less dense regions of the CsCl.
Rate zonal separates components based on their S-value, which determines how quickly the particles will move through a sucrose gradient. The greater the S-value, the more quickly it will move through the medium.

First of all, do I basically have the right idea about these methods?
Secondly, the book we are using in Biochem. doesn't say much about these methods, so I turned to my old Cell Bio. book. This book seems to imply that Isopycnic and Rate Zonal are only used for separating nucleic acids. Can these methods be used for separating other things, such as proteins from other proteins?

Sorry for the long-windedness, but I just feel like I am missing something important here.

Thanks in advance,
Taylor

[admin]

Hello,
yes you are correct.

Sedimentation Equilibrium or Isopycnic Centrifugation. Isopycnic or sedimentation equilibrium centrifugation involves allowing the sedimenting species to move through the gradient until they reach a point where their density and that of the gradient are identical.

See: Lecture 9

Also take a look at this amazing handout:
Centrifugation Handout

[jones106]

Awesome! Thank you very much, that was really helpful!

Taylor

[admin]

Hey Taylor,
No problem I am learning too

If you have any more questions or further information to add, please do.

Cheers

[baka]

Thank you so much .