The crosslink of a purified protein to NHS-activated magnetic beads works absolutely fine. But now I want to crosslink human skin tissue lysate to the beads and this does not work at all. The buffer does not contain amines (pure PBS). I personally assume that the high lipid content of the tissue lysate interferes with the esterification. Therefore, I need a quick and easy protocol for lipid extraction. I want to get rid of the lipids and purify the proteins from the skin tissue lysate. I tried two consecutive rounds of precipitation with acetone, but it didn't solve the problem. Any suggestions of how to get rid of lipids from skin tissue lysate?