Effect of proteinase inhibitors having antiinflammatory activity on gelatinase, elastase and cathepsin G isolated from rat polymorphonuclear leukocytes.

Abstract

Gelatinase, elastase and cathepsin G isolated from the granule extract of rat polymorphonuclear leukocytes (PMN) had similar properties to the enzymes of human PMN. Effect of proteinase inhibitors on these neutral proteinases isolated from rat PMN was studied. .epsilon.-Amino-n-caproic acid n-hexyl ester, a proteinase inhibitor with antiinflammatory activity, inhibited cathepsin G, whereas elastase was activated by the inhibitor. Leupeptin, L-1-tosylamide-2-phenylethyl chloromethyl ketone and N-.alpha.-p-tosyl-L-lysine chloromethyl ketone, antiinflammatory inhibitors, had no inhibitory effct on these neutral proteinases. Apparently, proteinase inhibitors reported as antiinflammatory agents exert their antiinflammatory actions not by direct inhibition of the neutral proteinases released from PMN but by other effects such as suppression of the infiltration of PMN into inflammatory locus.