A clearer understanding of the structure, biosynthesis and processing, and physiological roles of the complex carbohydrate-containing macromolecules of eukaryotic cells constitute the major long-range goals of this project. It is becoming increasingly apparent that many crucial physiological processes are related to the mobilization of glycoproteins that are destined for site-specific localization in membrane structures of the cell or for secretion. This project will focus on the regulation of synthesis of several plasma proteins as well as membrane proteins. Haptoglobin is a major plasma protein whose function is to sequester free hemoglobin to avoid kidney damage. We shall further clarify the details of enzymatic processing of this protein during and after secretion from the liver. Also, we shall attempt to define the factors that participate in the regulation of expression of the haptoglobin gene, particularly the dramatic induction of the gene in response to acute inflammation. Also the biosynthesis of a serum protease inhibitor, Alpha 1-antitrypsin, will be studied in rat liver with particular attention to the processing of this glycoprotein. These studies also shall be extended to a study of the synthesis and processing of human Alpha 1-antitrypsin in normal liver and liver from individuals with an inherited defect (ZZ), the properties of which suggest a defect in processing of this secretory protein. The cell surface-localized glycoproteins, rat hemoglobin-haptoglobin receptor and human transferrin receptor will be studied with regard to their biosynthesis and processing as well as their function in mediating the internalization of their respective ligands. The biosynthesis of the Golgi-localized glycoprotein, galactosyltransferase, will be studied using monoclonal antibodies as a probe for biosynthetic intermediates. We shall attempt to identify specific processing events involved in the synthesis that determine the site specific deposition of this protein in the Golgi apparatus. Monoclonal antibodies also will be used as probes to assess the structure and biosynthesis of surface glycoprotein markers of normal rat hepatocytes and cultured rat hepatoma cells.