title: Enzyme-linked immunoassay. Conjugation of rabbit anti-(human immunoglobulin G) antibody with beta-D-galactosidase from Escherichia coli and its use for human immunoglobulin G assay.
abstract: Rabbit immunoglobulin G (IgG) was reduced by incubating with 10 mM 2-mercaptoethylamine and then treated with excess amounts of N,N'-o-phenylenedimaleimide. As a result, maleimide residues were introduced into rabbit IgG molecules. Rabbit IgG containing maleimide residues could be coupled to beta-D-galactosidase from Escherichia coli which has sulfhydryl groups in the molecule. The resulting rabbit IgG (antibody)-enzyme complex may be useful for immunoassay of antigens. As an example, human IgG was assayed by the sandwich method using the rabbit anti-(human IgG) IgG-beta-D-galactosidase complex and amounts of human IgG as small as 3 fmoles were measurable.
mesh_terms: D000818:Animals; D001665:Binding Sites; D001666:Binding Sites, Antibody; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D005696:Galactosidases / Q000276:immunology*; D006041:Goats / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis*; D008301:Maleimides; D011485:Protein Binding; D011817:Rabbits / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D008301:Maleimides; D005696:Galactosidases