Stuctural glycoproteins (SGP) will be extracted from bovine, chick and human corneal stroma using techniques which minimize SGP breakdown and hydrolysis. SGP will be characterized with respect to molecular size and organization by molecular sieve chromatography and SDS polyacrylamide gel electrophoresis before and after reduction of disulfide bonds and with respect to amino acid and carbohydrate composition. SGP biosynthesis by stromal fibroblasts in culture will be studied via immunoassay procedures and chromatography utilizing antibodies prepared against purified SGP fractions. The chemical, immunological and biosynthetic properties of SGP will be compared to those of fibronectin and the extension peptides of procollagen. The changes in the content and synthesis of SGP will be studied in the developing chick embryo cornea.