Isolation, Purification, and the Amino Acid Sequence of a Secretory Trypsin Inhibitor from the Chicken Pancreas

A trypsin inhibitor is secreted in the pancreatic juice of the chick. Extracts from tissue have an inhibitor that corresponds to the secreted inhibitor on the basis of chromatography on DEAE-cellulose. The secretory inhibitor was purified by anion- and cation-exchange chromatography and by preparative isoelectric focusing. The purified inhibitor has 69 amino acids and is highly homologous with the secretory inhibitor from the turkey pancreas.