The Effect of the Oxidizing Agents Chloramine-T and Cigarette Smoke on Dog Serum Proteinase Inhibitor(s)

Abstract

Dog serum treated with the oxidant chloramine-T is rapidly and selectively depleted of its ability to inhibit porcine pancreatic elastase or dog neutrophil elastase. Trypsin inhibitory capacity of serum is not affected. Purified dog alpha-1-proteinase inhibitor (alpha-1-PI) is similarly oxidized with an apparent rate constant of 1.1 x 10(3) M-1 sec-1. Reversal of the oxidative inactivation using dithiothreitol was demonstrated. Cigarette smoke also directly affects the inhibitory capacity of both serum and pure alpha-1-PI. These studies form a basis for developing a model of functionally deficient alpha-1-PI by taking advantage of oxidative inactivation of normal proteinase inhibitor levels.