Polymorphic serum prealbumin (Pa) of pig, identified as an a!-protease inhibitor

Abstract
Pig serum proteins were analyzed by horizontal polyacrylamide gel electrophoresis with a discontinuous buffer system (pH 9.0). A 12% acrylamide concentration in the separation gel was used. Each of the 2 prealbumin (Pa) alleles gave rise to 2 closely migrating fractions. The polymorphic Pa was identified as an .alpha.1-protease inhibitor, as the Pa fractions inhibited the esterolytic activity of bovine trypsin and chymotrypsin. The locus symbol for this prealbumin should be changed to Pi-1. This protein was probably the same as the pig serum .alpha.1-protease inhibitor previously described and it evidently responds to human serum .alpha.1-protease inhibitor (Pi).