title: Tripeptidyl-peptidase II: a multi-purpose peptidase.
abstract: Tripeptidyl-peptidase II is a high-molecular weight peptidase with a widespread distribution in eukaryotic cells. The enzyme sequentially removes tripeptides from a free N-terminus of longer peptides and also displays a low endopeptidase activity. A role for tripeptidyl-peptidase II in the formation of peptides for antigen presentation has recently become evident, and the enzyme also appears to be important for the degradation of some specific substrates, e.g. the neuropeptide cholecystokinin. However, it is likely that the main biological function of tripeptidyl-peptidase II is to participate in a general intracellular protein turnover. This peptidase may act on oligopeptides generated by the proteasome, or other endopeptidases, and the tripeptides formed would subsequently be good substrates for other exopeptidases. The fact that tripeptidyl-peptidase II activity is increased in sepsis-induced muscle wasting, a situation of enhanced protein turnover, corroborates this biological role.
authors.affiliation: Department of Biochemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala, Sweden. birgitta.tomkinson@biokemi.uu.se
authors.forename: Birgitta
authors.initials: B
authors.lastname: Tomkinson
authors.forename: Ann-Christin
authors.initials: AC
authors.lastname: Lindås
mesh_terms: D000626:Aminopeptidases; D000818:Animals; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D005786:Gene Expression Regulation; D006801:Humans; D008954:Models, Biological; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology
chemical_list: D000626:Aminopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C048001:tripeptidyl-peptidase 2; D012697:Serine Endopeptidases; D046988:Proteasome Endopeptidase Complex