Abstract
The in-gel protein kinase assay is a powerful method to measure the protein phosphorylation activity of specific protein kinases. Any protein substrate can be embedded in polyacrylamide gels where they can be phosphorylated by protein kinases that are separated in the gel under denaturing conditions and then renatured. The kinase activity can be visualized in situ in the gels by autoradiography. This method has been used to compare the activities of protein kinases in parallel samples or to identify their potential substrates. Here, we describe in detail an in-gel kinase assay to measure the activity of some protein kinases in plants.