A chemiluminescent assay for quantitation of beta-galactosidase in the femtogram range: application to quantitation of beta-galactosidase in lacZ-transfected cells

Abstract

An optimized chemiluminescent assay for beta-galactosidase using a chemiluminescent substrate AMPGD (3-(4-methoxyspiro[1,2-dioxetane-3,2'-tricyclo-[3.3.1. 1(3,7)]decan]-4- yl)phenyl-beta-D-galactopyranoside) is described. This assay is rapid and sensitive and can detect as little as 2 fg of beta-galactosidase. Its use for the quantitation of beta-galactosidase in cells transfected with lacZ-expressing vectors is described. It is possible to detect a single cell stably expressing lacZ by this technique.