PSAP also known as Prosaposin is a member of the saposin family, which consists of four structurally related proteins—saposin A, B, C, and D—that are derived from the precursor protein prosaposin. PSAP plays a crucial role in lysosomal degradation of glycosphingolipids, acting as an essential cofactor for specific hydrolase enzymes. By modifying the lipid environment, PSAP enhances the accessibility of these enzymes to their substrates, thereby facilitating the breakdown of complex lipids. This function is particularly important in cellular metabolism and lipid homeostasis, as defects in PSAP have been linked to Gaucher′s disease, a genetic disorder characterized by glucocerebroside accumulation due to insufficient enzyme activity.