The objectives of this project are to investigate the biosynthesis of glycosaminoglycans and proteoglycans with the eventual aim of determining the overall mechanism of assembly. Microsomal preparations from chick embryo cartilage and mast cells will be utilized with sugar nucleotide precursors and PAPS to continue the delineation of the pathway of chondroitin sulfate biosynthesis. Microsomal preparations from mouse mast cell tumors will be utilized similarly with appropriate radioactively labeled sugar nucleotide precursors and PAPS to continue the delineation of the pathway of heparin biosynthesis. Microsomal preparations from the Englebreth-Holm-Swarm rat sarcoma and from cultured bovine endothelial cells will be utilized with appropriate radioactively labeled sugar nucleotide precursors and PAPS to delineate the pathway of heparan sulfate biosynthesis. In all of these cases the structure of the proteoglycans at the site of synthesis will be examined. Tissue cultures of endothelial cells producing heparant sulfate and of mast cells producing both heparin and chondroitin sulfate will be utilized to continue the investigation of the subcellular sites for proteoglycan biosynthesis. The processes of packaging and expert of the finished compounds will be followed. Radioactive precursors will be utilized to prelabel cartilage, tumors, and cells before obtaining subcellular fractions for investigation of sites for proteoglycan metabolism.
