Tissue sources of human serum alkaline phosphatase, as determined by immunochemical procedures.

The immunochemical differentiation of the alkaline phosphatases from tissues of the dog has been reported (2, 3). Antisera against dog intestinal phosphatase quantitatively precipitated this enzyme under conditions which were without effect on the alkaline phosphatases from liver and kidney of the same species. The potential value of this immunochemical approach for studies of tissue specificity of functionally similar enzymes and for establishing the origin of serum enzymes in normal and diseased states stems from the ability of antibodies to react specifically with and precipitate homologous antigens from mixtures of antigenically unrelated substances. This has prompted the present immunochemical investigation of preparations of alkaline phosphatases from human tissues. Studies on the specificity of the antibodies against several human tissues will be reported, as well as the use of these antibodies to establish the contribution by the tissues to the total alkaline phosphatase activity in serum.