Abstract
An N‐terminal region of the acid sphingomyelinase sequence (residues 89‐165) is shown to be homologous to saposintype sequences. By analogy with the known functions of saposins, this sphingomyelinase saposin‐type domain may possess lipid‐binding and/or sphingomyelinase‐activator properties. This finding may prove to be important in the understanding of Niemann‐Pick disease, which results from sphingomyelinase deficiency.