title: Characterization of antibody-chelator conjugates: determination of chelator content by terbium fluorescence titration.
abstract: Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.
authors.affiliation: Abbott Laboratories, Department 90M, Abbott Park, Illinois 60064.
authors.forename: K D
authors.initials: KD
authors.lastname: Brandt
authors.forename: K E
authors.initials: KE
authors.lastname: Schnobrich
authors.forename: D K
authors.initials: DK
authors.lastname: Johnson
mesh_terms: D000911:Antibodies, Monoclonal / Q000032:analysis*; D002272:Carcinoembryonic Antigen / Q000276:immunology; D002614:Chelating Agents / Q000032:analysis*; D003037:Cobalt Radioisotopes; D003432:Cross-Linking Reagents / Q000032:analysis; D004492:Edetic Acid / Q000032:analysis; D005453:Fluorescence; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives / Q000032:analysis; D004369:Pentetic Acid / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods; D013725:Terbium
chemical_list: D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D002614:Chelating Agents; D003037:Cobalt Radioisotopes; D003432:Cross-Linking Reagents; D013725:Terbium; D004369:Pentetic Acid; D004492:Edetic Acid; D009571:Nitrilotriacetic Acid