Sphingomyelinase and ceramidase in the intestinal tract

Sphingomyelin (SM) has emerged as an important source of lipid messengers affecting cell proliferation, differentiation and apoptosis. SM is present in mammalian cell membranes as a lipid constituent and also found as a component of dietary products such as milk, egg and meat. Digestion of SM has been found to have important implications in colon cancer development, gut maturation, and cholesterol absorption. SM in the intestine is sequentially digested by alkaline sphingomyelinase and neutral ceramidase before absorption. In the last decade, rapid progress has been made in many aspects of these two enzymes. The review intends to provide a short summary of the current knowledge on the properties, functions and the pathological changes of the enzymes in the intestinal tract.