Pepsinogen has been purified from the fundic mucosa of the dog. The preparation is homogeneous by chromatography, amino terminal analysis, ultracentrifugation, electrophoresis on cellulose acetate strips, and disc electrophoresis. Analysis indicates the presence of 352 amino acid residues, at least 12 moles of carbohydrate including some amino sugars, and 1 mole of organic phosphate per mole of...