Hello everybody, I just purified a membrane protein tagged with GFP, which has a cleavage site of precession protease. And I got a problem with removing the GFP tag by precession protease (1mM DTT and 1 mM EDTA were included in the buffer). It can not cut my protein. I have already tried to digest it in different detergent like DDM and C12E8 (also different concentration for detergent like lowering the detergent to 1.1 x cmc since a recent science paper lowered the detergent to this level and got it worked). I know this depends on the different proteins. I am wondering if anyone has this experience in digesting membrane protein by precession protease. Any suggestions are appreciated. Otherwise I might have to go back to just his-tag if there is no trick for that. Thank you so much in advance. All the best Qiangmin Zhang
