Structural studies on Pb proteins of the common and variant genetic types will be continued by performing sequential analysis. Monkey Pb proteins will also be studied by sequential analysis for the purpose of a biochemical evolutionary comparison. Attempts will be made to isolate and characterize precursor proteins of Pb from parotid glands. Sequential analysis will be performed on the proteins of the Pr-Db system to better understand their genetic and biochemical relationships. Possible functions of Pb and Pr-Db proteins will be studied by looking for a relationship between Pb and Pr-Db variant types and the incidence of caries and/or periodontal disease. Attempts will be made to determine cellular and subcellular localization of the Pb proteins using immunofluorescence techniques. Attempts will be made to identify new genetic polymorphisms in human saliva using sensitive protein staining methods, high voltage starch-gel electrophoresis techniques and radiolabeling of trace protein components with I125 followed by autoradiography. We will continue linkage studies of Pb and Pr-Db systems with many known genetic markers in order to assign them to specific linkage groups.