Palmitoyl Protein Thioesterase (PPT)

Palmitoyl Protein Thioesterase (PPT) is a lysosomal enzyme whose primary function is to cleave the thioester bond between fatty acids and cysteine in lipid-modified proteins, thereby removing long-chain fatty acids from the cysteine residues of proteins.
PPT includes two types, PPT1 and PPT2, both of which play crucial roles in lysosomal thioester catabolism, and PPT1 shares 26% amino acid sequence identity with PPT2. PPT1 hydrolyzes the thioester bonds linking fatty acids to cysteine residues in S-fatty acylated proteins. It is a homolog of PPT2 and is deficient in the lysosomal storage disorder, infantile neuronal ceroid lipofuscinosis (NCL). PPT2, like PPT1, targets lysosomes through the mannose-6-phosphate receptor pathway and exhibits high activity against palmitoylated model substrates such as palmitoyl-CoA. Additionally, PPT1 promotes tumor progression and serves as a molecular target for cancer drugs. Targeting PPT1 can block the mTOR signaling pathway and inhibit autophagy in a manner distinct from catalytic inhibitors, thus providing a new strategy for cancer treatment. However, studies on PPT2 in cancer are rarely reported.
PPT is involved in metabolic processes and can be utilized in research on cancer and neurodegenerative diseases^[1][2].

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