Various forms of rabbit plasma alpha-1-antiproteinase.

Amino acid sequencing of the ficin-derived C-terminal fragments of alpha-1-antiproteinase (also called alpha-1-antitrypsin or alpha-1-proteinase inhibitor) prepared from rabbit plasma revealed the presence of the E isoform, which had been confirmed in the cDNA library in addition to the F and S-1 forms. The S-2 form was identified in inflamed rabbit plasma. The ficin digest of human plasma alpha-1-antitrypsin resulted in a major fragment of the M type. Multiple forms of alpha-1-antiproteinase in the rabbit plasma implicate the unknown functions other than the inhibition of neutrophil elastase.