[RASMB] smaller protein size than expected

[fang.yi at yale.edu]

hello all,

I recently did sedimentation equilibrium runs on a protein (monomer size: 16
KD), at 3 concentrations (260, 130, 52 u M) at speeds of 25, 30, 35000 RPM.
Using Heteroanalysis, I could only fit the data into an ideal solution model,
with a monomer MW of 10KD.  Also, this protein runs at a MW lower than 
expected
on the gel filtration col also. SDS gel indicates it's the right size and not
degraded after the measurements.

Anybody has any suggestions why this protein appears to be such a "smaller"
protein?

Thanks a lot,

Fang Yi
Postdoc Fellow
Yale University
Molecular Biophysics and Biochemistry
New haven, CT 06511