Design and synthesis of a photocleavable biotin-linker for the photoisolation of ligand-receptor complexes based on the photolysis of 8-quinolinyl sulfonates in aqueous solution

Abstract

The ability of avidin (Avn) to form strong complex with biotin (Btn) is frequently used in the detection and isolation of biomolecules in biochemical, analytical, and medicinal research. The fact that the binding is nealy irreversible, however, constitutes a drawback in term of the isolation and purification of intact biomolecules. We recently found that 8-quinolinyl esters of aromatic or aliphatic sulfonic acids undergo photolysis when irradiated at 300-330 nm in aqueous solution at neutral pH. In this work, a biotin-dopamine (BD) conjugate containing a photocleavable 8-quinolinyl benzenesulfonate (QB) linker, BDQB, was designed and synthesized for use in the efficient recovery of dopamine-protein (e.g., antibody) complexes from an Avn-Btn system. The complexation of BDQB with a primary anti-dopamine antibody (anti-dopamine IgG1 from mouse) on an Avn-coated plate was confirmed by an enzyme-linked immunosorbent assay (ELISA) utilizing a secondary antibody (anti-IgG1 antibody) conjugated with horseradish peroxidase (HRP). Upon the photoirradiation (at 313 nm) of the BDQB-IgG1 complex, the release of dopamine-IgG1 complex was confirmed by ELISA. Characterization of the resulting photoreleased dopamine-anti-dopamine IgG1 complex was performed by SDS-PAGE and Western blot. © 2009 Elsevier Ltd. All rights reserved.