title: Synthesis and evaluation of aza-peptidyl inhibitors of the lysosomal asparaginyl endopeptidase, legumain.
abstract: Legumain or asparaginly endopeptidase (AEP) is a lysosomal cysteine protease with a high level of specificity for cleavage of protein substrates after an asparagine residue. It is also capable of cleaving after aspartic acids sites when in the acidic environment of the lysosome. Legumain expression and activity is linked to a number of pathological conditions including cancer, atherosclerosis and inflammation, yet its biological role in these pathologies is not well-understood. Highly potent and selective inhibitors of legumain would not only be valuable for studying the functional roles of legumain in these conditions, but may have therapeutic potential as well. We describe here the design, synthesis and in vitro evaluation of selective legumain inhibitors based on the aza-asparaginyl scaffold. We synthesized a library of aza-peptidyl inhibitors with various non-natural amino acids and different electrophilic warheads, and characterized the kinetic properties of inactivation of legumain. We also synthesized fluorescently labeled inhibitors to investigate cell permeability and selectivity of the compounds. The inhibitors have second order rate constants of up to 5 × 10(4)M(-1)s(-1) and IC(50) values as low as 4 nM against recombinant mouse legumain. In addition, the inhibitors are highly selective toward legumain and have little or no cross-reactivity with cathepsins. Overall, we have identified several valuable new inhibitors of legumain that can be used to study legumain function in multiple disease models.
authors.affiliation: Department of Pathology and Microbiology and Immunology, Stanford University School of Medicine, 300 Pasteur Dr. Stanford, CA 94305-5324, USA. jlee@kist.re.kr
authors.forename: Jiyoun
authors.initials: J
authors.lastname: Lee
authors.forename: Matthew
authors.initials: M
authors.lastname: Bogyo
mesh_terms: D000818:Animals; D001372:Aza Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D008247:Lysosomes / Q000201:enzymology*; D051379:Mice; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000099240:Asparaginyl Endopeptidase
chemical_list: D001372:Aza Compounds; D003546:Cysteine Endopeptidases; D004791:Enzyme Inhibitors; D010455:Peptides; D000099240:Asparaginyl Endopeptidase