[RASMB] one or two components

[judithk at vax2.concordia.ca]

I've been analyzing some velocity runs that were done at 42 000 rpm, 15 C,
for about 14 hours. When Iuse Sedfit and analyze the first 49 scans only
(the first 4.5 hours of the run), I find one, slightly asymmetric peak,
with S = 3.98 and a lot of material at less that 1.0 S. If, however, I
use the first 100 scans (9 hours of centrifuging) or all 150 scans, I have
two peaks, not totally separated, with S values of 2.93 (about 20% of the
total) and 4.19. In addition, the material at less than 1.0 S has almost
disappeared. Is this the way you expect species of about 45000 and 90000
to behave during a velocity run? Does this mean that one should never try
to use Sedfit unless the run has gone long enough that everything is at
the botton of the cell? Judith

Judith Kornblatt
Dept of Chemistry and Biochemistry
Concordia University
7141 Sherbrooke Ouest
Montreal, Qc H4B 1R6
Tel: 1 514 848 2424, ext 3384   FAX: 1 514 848 2868