Antibody has been prepared to alkaline phosphatase which is now greater than 98 percent homogeneous as determined by analytical polyacrylamide gel electrophoresis and meniscus depletion sedimentation equilibrium studies. At present, there appear to be two different antibodies raised in rabbits and we are attempting to isolate each. If successful, we hope to couple antibody to cyanogen bromide activated sepharose and greatly facilitate preparation of this enzyme. At present, it takes approximately six weeks and 100 rats to prepare 0.5 to 1.0 mg of the purest enzyme. We have lacked sufficient quantities of enzyme to do many of the studies that need to be done, such as determination of the carbohydrate content. With antibody, we will determine whether the increases in hepatic alkaline phosphatase reflect activation of a preformed enzyme or enzyme induction. We are studying catabolism of alkaline phosphatase, using whole rats with reticuloendothelial blockade and will use isolated peritoneal macrophages and Kupffer cells.