From: Carlos Alfonso Botello <carlosa@cib.csic.es>
  To  : rasmb@bbri.harvard.edu
  Date: Thu, 06 May 1999 13:19:02 +0200

Effect of TFE on vbar of proteins 2

Dear RASMBers:

We apologize for not explaining correctly our question. We do know that to
properly address this problem we have to measure the density increment
(d(rho)/dwpeptide) in the presence of 30%TFE. However, in order to do this
we have to do the density measurements with peptide samples in dialysis
equilibrium with 30% TFE. In our case, this equilibration step is not
trivial, because of the size of the peptide, the amounts we have, and its
stickiness to dialysis bags / filters. Because this is the first time we
have such problem we only have some preliminary density increment data for
BSA in 20-40% TFE. 

Therefore, our question is: Has anybody performed these density increment
exps. with other peptide/protein samples in TFE ?.  Perhaps with this
information we can make a rough estimation of the effect of TFE in our
peptide (while we figure out how to measure it in our system).

Best wishes to all.


Carlos Alfonso
Servicio de Ultracentrifuga Analítica
Centro de Investigaciones Biológicas
Velazquez 144
28006-Madrid
Tel: 91-5611800 Ext: 4401
Fax: 91-5627518
E-mail: carlosa@cib.csic.es