title: Vasoactive intestinal peptide hydrolysis by antibody light chains.
abstract: This paper describes evidence for hydrolysis of a neuropeptide, vasoactive intestinal peptide (VIP), by light chains purified from the IgG of a human subject positive for VIP binding antibodies. Purified IgG was digested with papain, resultant fragment antigen binding (Fab) fragments were reduced with 2-mercaptoethanol and alkylated with iodoacetamide, and light chains were purified by chromatography on immobilized antibodies to light chains and immobilized antibodies to heavy chains. Non-immunoglobulin components were undetectable in the light chain preparation, judged by sodium dodecyl sulfate-electrophoresis and Western blotting with anti-heavy and anti-light chain antibodies. The light chains hydrolyzed VIP with specific activity 32-fold greater than that of Fab, the pH optimum for light chain-mediated VIP hydrolysis was 7.0-7.5, and the hydrolytic activity was saturable (Vmax, 0.19 pmol/min/microgram light chains; substrate concentration at Vmax/2,380 nM).
authors.affiliation: Department of Pharmacology, University of Nebraska Medical Center, Omaha 68198-6260.
authors.forename: S
authors.initials: S
authors.lastname: Mei
authors.forename: B
authors.initials: B
authors.lastname: Mody
authors.forename: S H
authors.initials: SH
authors.lastname: Eklund
authors.forename: S
authors.initials: S
authors.lastname: Paul
mesh_terms: D001345:Autoradiography; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006868:Hydrolysis; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
chemical_list: D007140:Immunoglobulin Fab Fragments; D007147:Immunoglobulin Light Chains; D014660:Vasoactive Intestinal Peptide