The extracellular matrix proteins of the bones and teeth are key elements in the structure and metabolism of these tissues. The goal of this project is to study matrix proteins specific to each mineralizing skeletal tissue in order to understand their molecular structure and biological function. Analytical procedures (polyacrylamide gel electrophoresis, immunoblotting, specific dye-binging, RIA, ELISA, etc.) have been developed to quantitate the levels of noncollagenous proteins in bone including osteonectin, bone sialoproteins I and II, bone proteoglycans I and II, and the N-propeptide of type 1(I) collagen (formerly known as 24K phosphoprotein) in (a) surgical specimens of bony tissue and (b) serum (osteonectin). Changes in the noncollagenous protein profile with age and variety of bone (and tooth) diseases have been observed in man and several animal models. We have been highly successful at producing antisera against synthetic peptides for all of the human bone noncollagenous proteins. These antisera have proven useful in immunoprecipitation studies, immunolocalization, immunodetection on Western blots and in the isolation of full length cDNA of human bone osteonectin. proteoglycans I and II, and bone sialoproteins I and II.