Description_x000D_ General description_x000D_ The trypsin molecule has two domains: one is related to the enzyme active site and the tryptophan residues; the other is related to the 8-anilinonaphthalene-1-sulfonate binding._x000D_ Trypsin is a serine protease. The pancreas produce the precursor trypsinogen and secretes it to the intestine. Trypsinogen is converted to trypsin by enterokinase in the intestinal mucous membrane._x000D_ Application_x000D_ Trypsin has been used in a study to assess the similarities between the hepatitis E virus and human astrovirus. Trypsin has also been used in a study to characterize a unique technique for culturing primary adult human epithelial progenitor, or stem, cells._x000D_ Unit Definition_x000D_ One BAEE unit will produce a ΔA253 of 0.001 per min at pH 7.6 at 25 °C using BAEE as substrate. Reaction volume = 3.2 mL (1 cm light path)._x000D_ Quantity_x000D_ Minimum 1,000 BAEE units/vial_x000D_ Analysis Note_x000D_ Protein determined by E1%/280._x000D_ Other Notes_x000D_ View more information on trypsin at www.sigma-aldrich.com/enzymeexplorer