Comparison of β-D-Galactosidase from Escherichia coli and Horseradish Peroxidase as Labels of Anti-Human Ferritin Fab′ by Sandwich Enzyme Immunoassay Technique

Abstract

β-D-Galactosidase from Escherichia coli and horseradish peroxidase were compared as labels of anti-human ferritin Fab′ by sandwich enzyme immunoassay technique using fluorogenic substrates for enzyme assay. The anti-human ferritin Fab′ peroxidase conjugates gave lower nonspecific bindings and higher specific bindings than the corresponding Fab′-β-D-galactosidase conjugates. As a result, the former provided more sensitive dose response curves for human ferritin than the latter. However, the peroxidase conjugates were required in a larger quantity, since peroxidase assay was much less sensitive than β-D-galactosidase assay.