protein ladder detection for western blotting - (Sep/18/2006 )
I use prestained protein ladder for western blotting and HRP-conjugated seconder antibody so I use chemiluminesant detection for HRP. I should use labeled protein ladder. Is there HRP-conjugated protein ladder? Or can I use biotin-labeled protein marker and biotin detection pack with HRP detection kit? Thank you.
HRP will significantly alter the MW of the conjugates, so no one does that. Yes you can use biotinylated marker. But I just mark the position of prestained ladder with a sharpe on the film. Make sure the filter is fixed on the cassette so it will not move.
You don't need labeled protein weight markers. Right after transfer, do a red ponceau staining : you will check that your transfer was OK, and label the protein weight marker with a roller pen.
And then do as Genehunter suggested, trace the marker on the film.