PPT (Palmitoyl-Protein Thioesterase) refers to a class of enzymes involved in the depalmitoylation of lipid-modified proteins, including two main family members, PPT1 and PPT2. These enzymes are localized in cellular lysosomes and are primarily responsible for removing palmitoyl groups from proteins. PPT plays a crucial role in the health and functionality of neuronal cells, participating in cellular signaling and metabolic regulation. The gene expression of PPT1 and PPT2 is tissue-specific and closely associated with neurodegenerative diseases such as Batten disease. Mutations typically result in a loss of enzyme activity, thereby affecting cell function and survival.