Plasma protease inhibitor (PI) system in the laboratory opossum, Monodelphis domestica

Protease inhibitor (PI) polymorphism was observed in the laboratory opossum, Monodelphis domestica, by either one-dimensional acid polyacrylamide gel electrophoresis (PAGE; pH 4.6) or isoelectric focusing (pH 3.5-5.0) followed by immunoblotting with rabbit antiserum to human α-antitrypsin; but acid PAGE produced superior resolution of the PI proteins. Family studies demonstrated an inheritance of nine codominant autosomal alleles, PI(D), PI(E), PI(F), PI(G), PI(H), PI(I), PI(J), PI(K), and PI(M), and a population study revealed frequencies of 0.411, 0.010, 0.341, 0.034, 0.023, 0.071, 0.035, 0.020, and 0.055, respectively