Trypsin is used to enzymatically release adherent cells from tissue culture plates for passaging. Divalent cations such as calcium and magnesium, which are often present in the cell culture environment, inhibit this action. EDTA sequesters these ions and thus enhances the efficacy of trypsin. Trypsin is used to enzymatically release adherent cells from tissue culture plates for passaging. Divalent cations such as calcium and magnesium, which are often present in the cell culture environment, inhibit this action. EDTA sequesters these ions and thus enhances the efficacy of trypsin.