Pepsin Synonyms: Pepsin A, Pepsini pulvis, Pepsin from porcine gastric mucosa, pepsin from hog stomach mucosa CAS No.: 9001-75-6 EC No.: 3.4.23.1 Pepsin is a white to slightly yellow powder prepared from porcine gastric mucosa. Pepsin is an acidic digestive protease, which cleaves proteins at carboxylic groups of aromatic amino acids.  Jiagen Biotechnologies supplies quality Pepsin of various specifications. To place an order or for more information, please contact us at sales@jiagen.com.