title: Evaluation of beta-D-galactosidase from Escherichia coli and horseradish peroxidase as labels by sandwich enzyme immunoassay technique.
abstract: beta-D-galactosidase from Escherichia coli and horseradish peroxidase were evaluated as labels of Fab' in dose-response curves for human alpha-fetoprotein and human chorionic gonadotropin by sandwich enzyme immunoassay technique using fluorogenic substrates for enzyme assay. The non-specific binding of Fab'-peroxidase conjugates to IgG-coated polystyrene balls was less than that of Fab'-beta-D-galactosidase conjugates, and the affinity-purified Fab'-peroxidase conjugates gave more sensitive dose-response curves for these antigens than the corresponding beta-D-galactosidase conjugates. However, a large quantity of Fab'-peroxidase conjugates was required and a longer incubation was necessary for the peroxidase assay, since the peroxidase assay was much less sensitive than the beta-D-galactosidase assay. Other advantages and disadvantages of the two enzymes are discussed.
mesh_terms: D000937:Antigen-Antibody Reactions; D006063:Chorionic Gonadotropin / Q000276:immunology; D004926:Escherichia coli / Q000201:enzymology*; D005696:Galactosidases; D006735:Horseradish Peroxidase; D006801:Humans; D007124:Immunoenzyme Techniques; D007140:Immunoglobulin Fab Fragments / Q000032:analysis*; D008863:Microspheres; D010544:Peroxidases; D011137:Polystyrenes; D000509:alpha-Fetoproteins / Q000276:immunology; D001616:beta-Galactosidase
chemical_list: D006063:Chorionic Gonadotropin; D007140:Immunoglobulin Fab Fragments; D011137:Polystyrenes; D000509:alpha-Fetoproteins; D006735:Horseradish Peroxidase; D010544:Peroxidases; D005696:Galactosidases; D001616:beta-Galactosidase