title: Novel cell-permeable acyloxymethylketone inhibitors of asparaginyl endopeptidase.
abstract: Mammalian asparaginyl endopeptidase (AEP) or legumain is a recently identified lysosomal cysteine protease belonging to clan CD. To date it has been shown to be involved in antigen presentation within class II MHC positive cells and in pro-protein processing. Further elucidation of the biological functions of the enzyme will require potent and selective inhibitors and thus we describe here new acyloxymethylketone inhibitors of AEP. The most potent of the series is 2,6-dimethyl-benzoic acid 3-benzyloxycarbonylamino-4-carbamoyl-2-oxo-butyl ester (MV026630) with a kobs/[I] value of 1.09 x 10(5) M(-1) s(-1). At low microM concentrations this compound is able to enter living cells and irreversibly inactivate AEP. We show that this results in inhibition of AEP autoactivation and in perturbation of the processing and presentation of T cell epitopes from both tetanus toxin and myelin basic protein.
authors.affiliation: Medivir UK Ltd., Peterhouse Technology Park, 100 Fulbourn Road, Cambridge, CB1 9PT, UK.
authors.forename: Kylie
authors.initials: K
authors.lastname: Loak
authors.forename: Dongtao Ni
authors.initials: DN
authors.lastname: Li
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Manoury
authors.forename: Jeremy
authors.initials: J
authors.lastname: Billson
authors.forename: Fraser
authors.initials: F
authors.lastname: Morton
authors.forename: Ellen
authors.initials: E
authors.lastname: Hewitt
authors.forename: Colin
authors.initials: C
authors.lastname: Watts
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects; D000942:Antigens, Bacterial / Q000276:immunology; D001402:B-Lymphocytes / Q000187:drug effects / Q000201:enzymology / Q000276:immunology; D001565:Benzoates / Q000737:chemistry / Q000494:pharmacology*; D002384:Catalysis; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D015394:Molecular Structure; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001565:Benzoates; D015853:Cysteine Proteinase Inhibitors; C485023:MV026630