Two-dimensional immobilized metal affinity electrophoresis for capturing a phosphoprotein.

A two-dimensional immobilized metal affinity electrophoresis method is described here. In this method, ferric ions are immobilized in the second-dimensional polyacrylamide gel to extract the phosphoprotein β-casein from a mixture containing proteins with a broad range of pI and MW. Native 7.5-15% gradient tris-glycine gel with SDS tris-glycine gel running buffer are used so that proteins can be separated according to their molecular mass in the second dimension.