Description_x000D_ Packaging_x000D_ 25, 50 units in glass bottle_x000D_ Biochem/physiol Actions_x000D_ Initiates the formation of sphingomyelin-based second messengers. Activates MAPK (mitogen-activated protein kinase) and SAPKs (stress-activated protein kinases); generates ceramide from sphingomyelin._x000D_ Unit Definition_x000D_ One unit will hydrolyze 1.0 μmol of TNPAL-sphingomyelin per min at pH 7.4 at 37 °C._x000D_ Physical form_x000D_ Solution in 50% glycerol containing 0.25 M phosphate buffer, pH 7.5