SMS (Sphingomyelin Synthase) is a critical enzyme belonging to the transferase family. It consists of multiple domains and is primarily located in the endoplasmic reticulum and Golgi apparatus of cells. SMS is responsible for catalyzing the conversion of ceramide and phosphatidylcholine into sphingomyelin, which is an important component of cell membranes and myelin sheaths. By participating in the biosynthesis of sphingomyelin, SMS influences the structure and function of cell membranes, as well as the myelination process of nerve cells. The expression of the SMS gene is tissue-specific, and its mutations or functional abnormalities are associated with various diseases, including neurodegenerative diseases, metabolic disorders, and certain cancers.