in either type of cell derived from normal individuals , sphingomyelinase focused as a single peak ( pi = 5.60 +/- 0.1 ) while phosphodiesterases hydrolyzing bis ( 4-methylumbelliferyl ) phosphate and bis ( 4-methylumbelliferyl ) diphosphate separated into seven and three molecular forms respectively ;
C0037903
sphingomyelinase
C0031640
phosphodiesterases