title: Degradation of beta-amyloid by proteolytic antibody light chains.
abstract: Deposition of beta-amyloid (Abeta) is considered an important early event in the pathogenesis of Alzheimer's disease (AD). Clearance of Abeta thus represents a potential therapeutic approach. Antibody-mediated clearance of Abeta by vaccination inhibited and cleared Abeta deposition in animal models; however, inflammatory side effects were observed in humans. An alternative potentially noninflammatory approach to facilitate clearance is to proteolytically cleave Abeta. We screened 12 proteolytic recombinant antibody fragments for potential alpha-secretase activity, a naturally occurring enzyme that cleaves between the Lys16 and Leu17 residues of the amyloid precursor protein (APP). We utilized the synthetic alpha-secretase substrate, benzyloxycarbonyl-l-lysine o-nitrophenyl ester (Z-lys-o-Np) as a preliminary screen for alpha-secretase activity. Two antibody light chain fragments that hydrolyzed Z-lys-o-Np were identified. Abeta hydrolysis was studied using mass spectrometry to identify the cleavage patterns of the antibodies. The recombinant antibody light chain antibody fragment, c23.5, showed alpha-secretase-like activity, producing the 1-16 and 17-40 amino acid fragments of Abeta. The second light chain antibody fragment, hk14, demonstrated carboxypeptidase-like activity, cleaving sequentially from the carboxyl terminal of Abeta. These antibody light chains provide a novel route toward engineering efficient therapeutic antibodies capable of cleaving Abeta in vivo.
authors.affiliation: Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Srinath Kasturi
authors.initials: SK
authors.lastname: Rangan
authors.forename: Ruitian
authors.initials: R
authors.lastname: Liu
authors.forename: Daniel
authors.initials: D
authors.lastname: Brune
authors.forename: Stephanie
authors.initials: S
authors.lastname: Planque
authors.forename: Sudhir
authors.initials: S
authors.lastname: Paul
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sierks
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism; D053829:Amyloid Precursor Protein Secretases; D016229:Amyloid beta-Peptides / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases; D002268:Carboxypeptidases / Q000276:immunology / Q000378:metabolism; D002384:Catalysis; D002863:Chromogenic Compounds / Q000378:metabolism; D010450:Endopeptidases / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007128:Immunoglobulin Fragments / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000378:metabolism*; D007700:Kinetics; D008239:Lysine / Q000031:analogs & derivatives* / Q000378:metabolism; D013058:Mass Spectrometry; D051379:Mice; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D002863:Chromogenic Compounds; D007128:Immunoglobulin Fragments; D007147:Immunoglobulin Light Chains; D010446:Peptide Fragments; C084358:amyloid beta-protein (1-28); C055966:immunoglobulin Fv; C034117:N-benzyloxycarbonyllysine 4-nitrophenyl ester; D053829:Amyloid Precursor Protein Secretases; D002268:Carboxypeptidases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse; D008239:Lysine