The alteration of hamster serum elastase inhibitory capacities by chloramine T, in vitro and in vivo.

The major elastase inhibitor of human serum, alpha-1 proteinase inhibitor (A1PI), is susceptible to oxidative inactivation by a variety of agents, including chloramine T. We have examined the effects of chloramine T on the catalytic activity of porcine pancreatic (PPE) and human leukocyte elastase (HLE) and on the elastase inhibitory capacity of hamster, rat, and human serum as well as pure human A1PI. Both PPE and HLE, but not trypsin, were inhibited in a concentration-dependent manner by concentrations of chloramine T greater than 0.1 mM. The abilities of rat and human serum and pure human A1PI to inhibit both PPE and HLE were inhibited in a concentration-dependent manner by chloramine T. In contrast only the ability of hamster serum to inhibit HLE was altered by exposure to chloramine T: inhibition of PPE was not effected. Gel exclusion chromatography disclosed the existence of two major peaks of elastase inhibitory activity in hamster plasma: one, with an approximate molecular weight of 55 K, eluting in the region of A1PI that was sensitive to chloramine T inactivation and one with a molecular weight of approximately 180 K which was chloramine T insensitive. The parenteral administration of chloramine T to hamsters resulted in a modest and transient diminution of the serum HLE inhibitory activity and an equally modest and transient elevation of PPE inhibitory activity.