Lysosomal serine protease with tripeptidyl-peptidase I activity. May act as a non-specific lysosomal peptidase which generates tripeptides from the breakdown products produced by lysosomal proteinases. Requires substrates with an unsubstituted N-terminus.
Detected in all tissues examined with highest levels in heart and placenta and relatively similar levels in other tissues.
Defects in TPP1 are the cause of neuronal ceroid lipofuscinosis type 2 (CLN2) [MIM:204500]. A form of neuronal ceroid lipofuscinosis. Neuronal ceroid lipofuscinoses are progressive neurodegenerative, lysosomal storage diseases characterized by intracellular accumulation of autofluorescent liposomal material, and clinically by seizures, dementia, visual loss, and/or cerebral atrophy. The lipopigment pattern seen most often in CLN2 consists of curvilinear profiles.
Belongs to the peptidase S53 family.
Activated by autocatalytic proteolytical processing upon acidification. N-glycosylation is required for processing and activity.
Lysosome. Melanosome. Identified by mass spectrometry in melanosome fractions from stage I to stage IV.