Monoclonal antibodies block the trypsin cleavage site on human placental alkaline phosphatase

Three of eleven monoclonal antibodies (mAbs) to human placental alkaline phosphatase (PLAP) were shown to block cleavage by trypsin at the only proteolytically sensitive site on the native molecule. These results illustrate the potential importance of using mAbs to restrict proteolysis of proteins, in general, and serve as a novel means to identify the relative locations of antigenic determinants.