[RASMB] hsa

[Ariel Lustig]

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