I will be doing some precipitations with 8.5% PEG. My buffer also contains 760 ug/ml heparin. Since I need to resuspend the pellet and cross-link the proteins with NHS ester I am seeking the knowledge of someone who may know the answer. Heparin contains secondary amines, which could mess up my NHS ester reactions. I didn't had any chance finding the answer while looking in the literature.

Please don't bother responding that I may do some dialysis or desalting etc. to make sure there is no heparin in the precipitate.