Using centrifugal filter units to concentrate protein - (Feb/28/2013 )

I think it is protein dependent. Much of my work is with antibodies who behave fine at room temp so 4C isn't necessary but with some proteins crudely purified from lysates I've been more concerned and spun @ 4C and it was fine but it takes a long time. I wouldn't do it unless I had reason to believe it was necessary.