same protein produced in different cell lines

[newsnet customer]

> Hi all -
>
> I'm testing two versions of the same protein, given to me by two
> collaborators. One was produced in BHK cells (stable transfection), and
> the other in COS-7 cells (transient transfection). I was trying to test
> how these constructs bind to my target protein, and strangely enough,
> they are behaving differently in the binding assays. Does anyone have
> insight on why this might be happening, i.e., differential
> glycosylation? Thanks!
>
> Samira

Two possibilities:

- Transient transfection will produce less protein than stable transfection.
- Endogenous proteins in COS-7 cells are interacting with your target 
protein.
- Less likely is: differential splicing and post-translational modification 
in COS-7 cells.

ST