Phosphatase Inhibitor Cocktail effectively inhibits L-isozymes of alkaline phosphatase and serine/threonine protein phosphatases, such as the PP1 (protein phosphatase 1) and PP2A (protein phosphatase 2a) proteins. Crude cell extracts contain a number of endogenous enzymes, such as proteases and phosphatases, which are capable of modifying the proteins present in the extract. The best way to improve the yield of intact proteins is to add inhibitors of these enzymes known to be present in the source material. Recommended for use with tissue and cell extracts, including extracts containing detergents.