You find that the integral membrane protein you are studying is modified on the cytosolic side in an enzyme-mediated reaction. If cells are lysed and centrifuged and the pellet broken up in the appropriate buffer, your protein is still modified with no additional proteins added. If the cell lysate is treated 0.2 M KCl and then centrifuged, your protein is still in the pellet but it is not modified. Explain your results.