This 3,3'5,5’- tetramethylbenzidine (TMB) is an insoluble chromogen substrate for horseradish peroxidase detection systems for Membrane (for Western, Northern, Southern, Slot or Dot Blots). This is ready to use one component system and gives aqua marine bands with peroxidase. This TMB solution contains TMB, 1.13 mMol L-1, Hydrogen Peroxide substrate, 1% DMSO, acetate buffer, pH 4.9 and non-toxic proprietary stabilizers.