Function
Tripeptidyl peptidase (TPP) is an enzyme which cleaves N-terminal tripeptides from polypeptides.
- TPP-I functions in lysosomes.
- TPP-II is part of the ubiquitin-proteasome pathway.
- TPP-IV is a serine exopeptidase which cleaves proline dipeptides from the N-terminus of polypeptides.
Didease
TPP-I participates in lysosomal turnover of proteins in pathological conditions associated with cell injury and its mutations cause the fatal neurodegenerative childhood neuronal ceroid lipofuscinosis[1]. TPP-II deficiency is linked to severe autoimmunity[2]. TPP-II has central and peripheral roles in metabolism and hence in fat formation[3].
Structural highlights
TPP-I catalytic triad is the typical and the active site contains an [4].