[Albert]

Hello everybody.
Talking about centrifugation, one of its applications is determining proteins's molecular weight. However it can be used for separating proteins from mitochondria and nuclei (for example). The two procedures are different, I think also for what concerns machinery and time.

Now, here is my question. My professor gave us a test-yourself exercise and one of the statements is:

'In order to separate proteins using centrifugation, a low rate centrifuge is sufficient.'

Is it true or false? In my opinion it is just a matter of which kind of procedure we are talking about.

[Mitch]

You just use a centrifugal cut-off filter.

[Albert]

Ok, thank you very much.

So, to sum up, for this kind of process a low-rate centrifuge is sufficient...and it doesn't take you too much time, does it?

[Mitch]

You put your extract into the centrfugal cut-off filter go read your e-mail and come back.

[Yggdrasil]

If you just want to separate components of a mixture (e.g. insoluble cell debris from a cell lysate) then a low rate centrifuge is sufficient.  However, if you want to determine the molecular weight of a protein/separate two proteins of similar molecular weight by equilibrium sedimentation, you need a high-rate centrifuge.