Protein Molecular Weight Marker is designed for use in accurate estimation of protein molecular weight in SDS-polyacrylamide gel electrophoresis and western blotting. It contains: [62.5 mM Tris-HCl, pH 6.8, 2% (w/v) SDS, 250 mM NaCl, 1mM EDTA, 4% (v/v) ß-Mercaptoethanol, 35% (v/v) Glycerol and 0.05% (w/v) bromophenol blue.] Thaw the cocktail at room temperature. Gently invert vial several times to ensure that the solution is homogeneous and that any precipitated material is re-dissolved. A loading volume of 5-10µl is appropriate for most gel formats.