Tripeptidyl-Peptidase 1 (TPP1) belongs to the peptidase S53 family. TPP1 is detected in all tissues examined with highest levels in heart and placenta and relatively similar levels in other tissues. TPP1 is lysosomal serine protease with tripeptidyl-peptidase I activity. TPP1 may act as a non-specific lysosomal peptidase which generates tripeptides from the breakdown products produced by lysosomal proteinases. TPP1 requires substrates with an unsubstituted N-terminus. TPP1 mutations have also been shown to cause neuronal ceroid lipofuscinosis type 2 (CLN2).
