The specific aims of this project are to explore the chemical composition of mucus glycoproteins contained in porcine gastric mucosal secretions of single donor animals. Experimental techniques will include isolation of the gelatinous (gel) mucoproteins from the water soluble mucoproteins; purification of the gel mucoproteins by molecular seive and high pressure liquid chromatography, sucrose density centrifugation and gel electrophoresis; utilization of proteolytic enzymes as tools of structural analysis; determination of the amino acid composition of the native glycoprotein and its proteolytic digests; and an assessment of the number of subunits in the native molecule. The protective function of the mucus blanket lies in its constituent proteins and glycoproteins and has so been indicated in many disease states such as cystic fibrosis, fucosidiosis, chronic bronchitis and asthma, as well as gastric ulceration. It has also been determined that any changes in the composition of the glycoprotein component will alter the physical properties of the gastrointestinal mucus layer and can be a contributing factor to such disorders as ilitus, peptic ulcers, colitus and gastritis. It is therefore imperative to acquire a more precise definition of the structural relationship of mucus components which will lead to a better understanding of the possible role of mucus structure in diseased states.