[RASMB] peptide concentration

[Schar, Christine]

Hello

I basically have 2 questions.  How high of a concentration of peptides can
you run with interference optics in a sedimentation velocity experiment? 
And what are the odds of recovering usable peptide after the run?

For a little background, I ran some peptides (12-33 aa in length, no 
tryptophan or tyrosine) using interference optics in an SV run (400ul
sample) to check for self-association of the peptides.  I ran the samples
at a concentration of 4 mg/ml to mimic what they have used in experiments
before as well as conserve their peptides.  However, there was no evidence
of self-association.  Turns out they have seen aggregation using AFM at a
concentration of 40 mg/ml.  Now they would like to confirm this by AUC. 
And they would like to get their sample back.  Hence my 2 questions.

Any advice would be appreciated.
Christine