RB site EMSA (Electrophoretic-Mobility Shift Assay) kit is used for monitoring RB site (Retinoblastoma control element) DNA binding activities and activation. Upon activation, RB site can recognize and interact with the unique DNA binding sequence and form protein/DNA complex, which can be separated from free DNA due to the differences in their electrophoretic mobility in native (non-denaturing) polyacrylamide gels.