A monoclonal antibody that reacts with nonallelic enzyme glycoproteins.

One of six monoclonal antibodies raised against purified human placental alkaline phosphatase cross-reacts with the adult and fetal forms of intestinal alkaline phosphatase. The placental and intestinal enzymes are nonallelic. A new electrophoretic titration procedure was used to assess the relative reactivities of the different enzymes with the antibody. The placental enzyme was the most reactive. However, the adult intestinal enzyme showed greater reactivity than the fetal enzyme. The determinants to which the antibody binds on these three forms of alkaline phosphatase presumably differ in their detailed molecular configurations.