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 was rapidly and selectively depleted of its ability to inhibit porcine pancreatic elastase or dog neutrophil elastase. Trypsin inhibitory capacity of serum was not affected. Purified dog .alpha.-1-proteinase inhibitor (.alpha.-1-PI) was also oxidized with an apparent rate constant of 1.1 .times. 103 M-1 s-1. Reversal of the oxidative inactivation using dithiothreitol was demonstrated. Cigarette smoke directly affected the inhibitory capacitity of serum and pure .alpha.-1-PI. These studies formed a basis for developing a model of functionally deficient .alpha.-1-PI by taking advantage of oxidative inactivation of normal proteinase inhibitor levels.