Ectonucleotide pyrophosphatase/phosphodiesterase family member 7 (ENPP7), also known as alkaline sphingomyelin phosphodiesterase or intestinal alkaline sphingomyelinase, converts sphingomyelin to ceramide in the intestinal tract [, ]. Crystal structure reveals a specific aromatic box composed of tyrosine residues which recognises the choline moiety in its substrates, a hydrophobic loop, and positively charged surfaces for contacting bile salt micelles []. It is also able to inactivate the pro-inflammatory phospholipid PAF (platelet-activating factor) by a phospholipase C activity, and may counteract the development of intestinal inflammation and cancer [, ]. It does not appear to have nucleotide pyrophosphatase activity [].
