Unusual behaviour of protein on SDS-PAGE gels - any suggestions?

Hiranya Roychowdhury hroychow at NMSU.EDU
Fri Apr 24 10:28:45 EST 1998

At 12:54 PM 4/24/98 +0000, David wrote:
>A protein that our group is studying on shows strange behaviour on
>SDS-PAGE gels:
>if not boiled before loading, it runs as one band, whereas if one boils it
>first, it runs as two bands: one of these runs the same as the band one
>sees without boiling, but the strange thing is that a second band appears,
>which migrates *less* than the first one (by an amount equivalent to a few
>kDa), so it cannot just be a degradation product. If anyone has any
>suggestions as to why this might be happening, please let me know, and
>I'll pass them on; has anyone seen something like this before?
>Thank you very much,
>das1002 at cam.ac.uk

Could it be that the non-reduced protein migrates faster due to its globuler
nature (smaller Stoke's radius)? Upon complete denaturation by boiling, the
two component polypeptides (subunits?) of the same protein, now dissociated,
run more according to their Mr? 

Dr. Hiranya Sankar Roychowdhury
Plant Genetic Engineering Lab.
New Mexico State University
Las Cruces, NM 88003
Ph. (505) 646-5785
hroychow at nmsu.edu

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