2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-lLiquid Substrate System is supplied as a ready-to-use peroxidase substrate containing 2,2'-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) in an acidic buffer. The substrate should be colorless prior to reaction with peroxidase. It will develop a blue-green reaction product when reacted with peroxidase in microwell applications (e.g. ELISA assays). For end-point assays, 1% sodium dodecyl sulfate (SDS) may be used to stop the reaction. This will also result in a blue-green end product. Since this substrate produces a soluble reaction product, it is not recommended for blotting or histochemical applications.