Selective staining of alpha1-antitrypsin (alpha1-protease inhibitor) with Schiff's reagent after separation from serum by analytical isoelectrofocusing in polyacrylamide gel.

After electrofocusing serum from human and various animals in the pH range 4.0-6.0, only the isoproteins of antitrypsin stain with Schiff's reagent. As an additional advantage, this staining provides information about the relative contents of the Schiff-positive carbohydrates of various antitrypsins.