Digestive enzyme
Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption by the body. Digestive enzymes are found in the digestive tracts of animals (including humans) and in the traps of carnivorous plants, where they aid in the digestion of food, as well as inside cells, especially in their lysosomes, where they function to maintain cellular survival. Digestive enzymes of diverse specificities are found in the saliva secreted by the salivary glands, in the secretions of cells lining
ENPP7
ENPP7 is the key enzyme in the gut that digests sphingomyelin. Sphingomyelin is a lipid constituent of cell membrane, and a dietary component being particularly abundant in milk, cheese, egg, and meat. Digestion of sphingomyelin mainly occurs in the middle part of the small intestine, where ENPP7 is abundant, indicating a role of the enzyme in sphingomyelin digestion. Recent studies on ENPP7 knockout mice clearly showed that digestion of sphingomyelin and generation of ceramide is severely affected in ENPP7 deficiency mice. ENPP7 is fully developed in the intestine before birth, which gives the infant ability to digest sphingomyelin in the milk.