Super TMB ELISA Substrate is a ready-to-use chromogenic substrate for detection of horseradish peroxidase (HRP) activity. HRP can catalyze 3,3',5,5'-tetramethylbenzidine (TMB) to yield a blue color, the maximal absorbance is at 370 nm or 620-652 nm. Upon addition of the stop solution, the solution turns to yellow and can be measured at 450 nm. This one-component method is 40-50% more sensitive than the traditional TMB ELISA method.