Phospholipases C are defined as enzymes that catalyze the hydrolysis of phospholipids into 1,2-diacylglycerols (or N-acylsphingosine in the case of sphingomyelin) and phosphate monoester. Some of the phospholipaes C act best towards phosphatidylcholine (sometimes referred to as PC-specific phospholipase C) and show some activity towards other phospholipids. Other phospholipases C act optimally on phosphatidyinositol (Pi-specific phospholipase C). Sphingomyelinases carry out the same type of reaction, and some of phospholipases can also utilize sphingomyeline as a substrate (11).