Naturally occurring low molecular weight inhibitors of neutral proteinases from PMN-granulocytes and of kallikreins

Abstract

Human mucous secretions contain low molecular weight (M _r ∼11,000) acid-stable inhibitors directed against elastase and cathepsin G from PMN-granulocytes. Important biochemical properties of these inhibitors are presented and their possible biological function is discussed. An inhibitor of glandular and plasma kallikreins preventing kinin-liberation from kininogen but not ester hydrolysis was obtained from rat kidney tubules. A molecular weight of about 4700 was estimated for this kallikrein-specific inhibitor (trypsin-induced kinin-liberation is not prevented).