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<DIV><FONT face=Arial size=2>Dear Yiming, dear colleagues,</FONT></DIV>
<DIV><FONT face=Arial size=2>We all know that HSA, as all other
Albumins is a part of natural Serum Complex that may aggregate
also after purification</FONT></DIV>
<DIV><FONT face=Arial size=2>and fractionation. Usually we run it in
buffer that is close to the natural medium (blood) concering pH,
ioning-strength, salts etc...</FONT></DIV>
<DIV><FONT face=Arial size=2>As we know that it has a spheric shape ,
the concentration dependence at the ideal concentration
range 0 to 0.3mgmL is very</FONT></DIV>
<DIV><FONT face=Arial size=2>small the S°<FONT size=1>20</FONT>w
(extrapolated to zero concentration) is between 4.3 to 4.6 S'
and it appears mainly in tables where not always</FONT></DIV>
<DIV><FONT face=Arial size=2>is defined the Vbar, (about
0.74) exact buffer consistence and the buffer -physical parameters
used. Luckily albumin does not</FONT></DIV>
<DIV><FONT face=Arial size=2>dissociate in subunits par example like
haemoglobin when using high salt concentration or at a concentration
range </FONT></DIV>
<DIV><FONT face=Arial size=2>of 0 to 0.05mgmL so that
extrapolated values are real-values.</FONT></DIV>
<DIV><FONT face=Arial size=2>The same story possible to adapt
to many many other proteins !! </FONT></DIV>
<DIV><FONT face=Arial size=2>I ask myself, whatfore one needs a
standard - S' value ? sure not to calibrate the rotor speed
!!</FONT></DIV>
<DIV><FONT face=Arial size=2>To compare precisely S' values make no sense
......yours ariel</FONT></DIV>
<DIV><FONT face=Arial size=2><A
href="mailto:ariel.lustig@bluewin.ch">ariel.lustig@bluewin.ch</A></FONT></DIV></BODY></HTML>