PeppermintStick™ phosphoprotein molecular weight standards are a mixture of phosphorylated and nonphosphorylated proteins ranging from 14,400 to 116,250 molecular weight. Separation by polyacrylamide gel electrophoresis resolves the standard mixture into two phosphorylated and four nonphosphorylated protein bands. PeppermintStick™ phosphoprotein molecular weight standards are also available in a 400 µL volume (P33350}.