gst- pulldown - (Dec/30/2010 )

hi. i am doing gst-pulldown however i got inconsistent results sometimes. I just want to ask what major factors could have caosed this inconsistent results....

i would like to measure the activity of a certain protein in the cell and i expect that the amount of the protein in the pulldown will be different ( increase or decrease) however, when i did the pulldown again, all signals are the same. I used exactly the same conditions.

what could have be possible reasons for this. thank you....

are you sure you had excess antibody?