title: Characterization of the endopeptidase activity of tripeptidyl-peptidase II.
abstract: Tripeptidyl-peptidase II (TPP II) is a giant cytosolic peptidase with a proposed role in cellular protein degradation and protection against apoptosis. Beside its well-characterised exopeptidase activity, TPP II also has an endopeptidase activity. Little is known about this activity, and since it could be important for the physiological role of TPP II, we have investigated it in more detail. Two peptides, Nef(69-87) and LL37, were incubated with wild-type murine TPP II and variants thereof as well as TPP II from human and Drosophila melanogaster. Two intrinsically disordered proteins were also included in the study. We conclude that the endopeptidase activity is more promiscuous than previously reported. It is also clear that TPP II can attack longer disordered peptides up to 75 amino acid residues. Using a novel FRET substrate, the catalytic efficiency of the endopeptidase activity could be determined to be 5 orders of magnitude lower than for the exopeptidase activity.
authors: Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, 751 23 Uppsala, Sweden. sandra.eklund@imbim.uu.se
authors: Sandra
authors: S
authors: Eklund
authors: Jakob
authors: J
authors: Dogan
authors: Per
authors: P
authors: Jemth
authors: Hubert
authors: H
authors: Kalbacher
authors: Birgitta
authors: B
authors: Tomkinson
mesh_terms: D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D000818:Animals; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D004331:Drosophila melanogaster / Q000201:enzymology; D010450:Endopeptidases / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; D010450:Endopeptidases; D000626:Aminopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C048001:tripeptidyl-peptidase 2; D012697:Serine Endopeptidases