In Article <5b5d7j$4ek at ccshst05.cs.uoguelph.ca>, wyu at uoguelph.ca (Wenjin Yu)
wrote:
>Dear colleagues,
>> We've isolated and cDNA encoding a protein which should have a
>weight of 25 kD dased on computer program calculation. However, after we
>did Western blot using antibodies specific to this protein we got a 33kD
>band on SDS-PAGE (under reduced conditions). Although this protein is a
>glycoprotein, it shouldn't change so much since only one glyco-site was
>found. Does any one can explain this for me? Any suggestions are highly
>appreciated.
This is not an uncommon phenomenon. It has been discussed here before, with
suggestions ranging from extreme pI to regions of high proline content as
possible explanations. The whole cadherin class of cell adhesion molecules
show this kind of anomalous migration (predicted molecular weight about 80
kD, Laemmli gels show about 110-120 kD, deglycosylated). One thing you can
try is running a Weber Osborn gel, with phosphate buffer and no stacking;
this system doesn't seem to give such anomalous mobilities.
Warren Gallin
Department of Biological Sciences
University of Alberta
Edmonton, Alberta T6G 2E9
Canada
wgallin at gpu.srv.ualberta.ca
