Electrophoretic characterization of porcine pancreatic (pro)elastases A and B

Two porcine pancreatic zymogens can be separated by free electrophoresis on a sucrose gradient. After activation by trypsin, both enzymes can hydrolyze completely the fibrous protein elastin. One of the two proteins, proelastase B, has, in addition, an esterolytic activity towards N-acetyl-L-tyrosine ethyl ester. The other, proelastase A, does not possess it. The activation products of the zymogens have been tagged with radioactive diisopropylfluro-phosphonate and separated by polacrylamide-gel electrophoresis. Proelastase A gives only one active species, pancreatopeptidase E, but three distinct proteins can be obtained from proelastase B. Elastases A and B exhibit an important synergism when acting together upon a purified elastin lacking microfibrils. Trypsin has considerably less synergistic activity, and chymotrypsin has practically none.