Description_x000D_ Application_x000D_ Pepsin is a peptidase used to digest proteins and is commonly used in the preparation of Fab fragments from antibodies. Pepsin, from porcine gastric mucosa, has been used to hydrolyze dry cervical samples in mice._x000D_ The enzyme from Sigma has been used in the digestion of crude wheat gliadin. It has been used along with other enzymes to demonstrate the effects of fixation and enzymatic digestion in immunohistochemical assays, using paraffin embedded tissue. It has been used for digestion (before using immunoperoxidase techniques) to reduce non-specific background staining in sections of bronchial tissues. The enzyme has also been used in the preparation of F(ab)2 fragment from IgG._x000D_ Pepsin cleavage can be used to produce F(ab')2 fragments of antibodies. pepsin at www.sigma-aldrich.com/enzymeexplorer._x000D_ Packaging_x000D_ 1, 5, 10, 25, 100 g in poly bottle_x000D_ 250 mg in poly bottle_x000D_ Biochem/physiol Actions_x000D_ Pepsin hydrolyzes peptide bonds, not amide or ester linkages. Pepsin cleaves peptides with an aromatic acid on either side of the peptide bond. Sulfur-containing amino acids increase susceptibility to hydrolysis when they are close to the peptide bond. Pepsin preferentially cleaves at the carboxyl side of phenylalanine and leucine and at the carboxyl side of glutamic acid residues. Cleaves Phe-Val, Gln-His, Glu-Ala, Ala-Leu, Leu-Tyr, Tyr-Leu, Gly-Phe, Phe-Phe and Phe-Tyr bonds in the β chain of insulin_x000D_ Pepsin is the major proteolytic enzyme produced in the stomach. It digests proteins through the cleavage of interior peptide linkages._x000D_ The enzyme does not cleave at valine, alanine, or glycine linkages. Z-L-tyrosyl-L-phenylalanine, Z-L-glutamyl-L-tyrosine, or Z-L-methionyl-L-tyrosine may be used as substrates for pepsin digestion. Pepsin is inhibited by several phenylalanine-containing peptides._x000D_ Preferential cleavage: hydrophobic and aromatic residues in P1 and P1′ postitions. Cleaves Phe-Val, Gln-His, Glu-Ala, Ala-Leu, Leu-Tyr, Tyr-Leu, Gly-Phe, Phe-Phe and Phe-Tyr bonds in the β chain of insulin_x000D_ Unit Definition_x000D_ One unit will produce a ΔA280 of 0.001 per min at pH 2.0 at 37°C, measured as TCA-soluble products using hemoglobin as substrate. (Final volume = 16mL. Light path = 1cm.)_x000D_ Analysis Note_x000D_ E1%/280=14.7_x000D_ Optimum pH is 2-4. Active in 4 M urea and 3 M guanidine HCl. Stable at 60 °C. Pepsin is irreversibly inactivated at pH 8.0 - 8.5._x000D_ Protein determined by E1%/280_x000D_ Other Notes_x000D_ View more information on pepsin at www.sigma-aldrich.com/enzymeexplorer.