Abstract
To date, there have been accumulated the numerous reports suggesting the significant roles of sphingomyelin metabolism in the intracellular signal transduction such as the apoptosis pathway. Despite extensive studies, however, the precise function of each enzyme is still obscure and some of observations appear to be controversial. The confusions could be partially due to the insufficient information concerning molecular species, structures, and functions of sphingomyelin metabolic enzymes. Therefore, in this article, I tried to overview the pathophysiological significance of sphingomyelin metabolic enzymes from the viewpoint of protein structures. Serine palmitoyltransferase which is responsible for the first step in the sphingomyelin synthetic pathway, and sphingomyelinase and ceramidase which are responsible for the first and second steps in the sphingomyelin hydrolytic pathway are mainly described.
