Unit Definition One unit will hydrolyze 1.0 μmole of TNPAL-sphingomyelin per min at pH 7.4 at 37 °C.
Physical form Solution in 50% glycerol containing 50 mM Tris-HCl, pH 7.5.
Biochem/physiol Actions Initiates the formation of sphingomyelin-based second messengers. Activates MAPK (mitogen-activated protein kinase) and SAPKs (stress-activated protein kinases); generates ceramide from sphingomyelin.