Protein dye

A reversible general protein stain is used after the transfer step to check whether the transfer was successful before starting the detection of specific proteins with antibodies. The most commonly used dye is called Ponceau S. It binds to all proteins and gives them a red-pink color that can be seen with the naked eye. If the membrane looks as expected, the dye can be easily removed again by washing, and the membrane can then be blocked and probed with antibodies.