From: Geoff=Howlett%BioChem%UNIMELB@muwaye.unimelb.EDU.AU
  To  : rasmb@bbri.eri.harvard.edu
  Date: Wed, 25 May 94 20:25:07 +1000

vbars

I am surprised Tom Laue gets the same molecular weight using tris buffer 
compared with using 6M guanidine.  I thought preferential hydration became a 
problem in high salt.  ie. The guanidine gets excluded from the protein more 
effectively than water leading to an effect on buoyancy.  Is this correct?

The related question I have is whether the accuracy of the XLA data might 
allow experiments using H2O and D2O.  This approach has the potential to 
solve for  both the vbar and molecular weight value.  We have done this with 
some degree of success with phospholipid emulsions.  The problem gets a 
little tougher when you start to look at proteins.

I share Tom's interest in whether anyone has measured vbars lately and 
whether they agree with the value estimated from composition.  Is there 
anyone out there...

Geoff Howlett