Pancreatic anionic trypsin: Evidence for the existence of a 30 kDa form

Abstract

1. 1. An anionic form of trypsin has been isolated from pancreas of various species (rat, pig, dog and cow). 2. 2. The purification procedure included affinity chromatography on STI-Sepharose 4B and ion-exchange chromatography on DEAE-Sephadex A-50. 3. 3. The preparation was homogeneous as checked by SDS-polyacrylamide slab gel electrophoresis, resulting in an estimated molecular weight of 30 kilodaltons (kDa) for this anionic form. 4. 4. Antibodies against the anionic form from rat pancreas cross-reacted towards the anionic enzyme from porcine pancreas but not with the dog or bovine enzyme, nor with all the studied cationic forms. 5. 5. Limited proteolysis of tubulin, a cytoskeletal protein, with an anionic or cationic form of trypsin showed striking differences in the size of produced peptides.