DUAL NATURE OF THE REACTION BETWEEN PORCINE ELASTASE AND HUMAN-PLASMA ALPHA-1-PROTEINASE INHIBITOR

Only a portion of human plasma α1 proteinase inhibitor (α1PI) forms a 1:1 complex with porcine elastase; the other portion is inactivated via proteolysis. High temperature (37°) and high salt (2 M) enhance complex formation. The complex is unstable, but no significant liberation of active elastase could be demonstrated. Probably the same two major products of ∼50,000 and ∼4,000 daltons are formed from α1PI via proteolysis and via disintegration of the complex. Iodination of α1PI or oxidation with chloramine-T prevents complex formation with elastase but not with trypsin. Iodinated elastase, however, forms a complex with α1PI. © 1979.