[Inhibition of human granulocyte proteinases by a heat and acid-stable proteinase inhibitor from rabbit serum].

Several human granulocyte proteinases sensitive to the thermo- and acid-resistant proteinase inhibitor from rabbit serum (TASPI) were revealed, using TASPI-Sepharose 4B. It was found that TASPI inhibits the following human granulocyte proteinases: granules-localized kininogenase and chymotrypsin-like kininase (serine proteinases), elastase-like proteinase and benzoyl arginine ethyl ester esterase, as well as chymotrypsin-like kininase from the post-granule supernatant. These enzymes were compared to known granulocyte proteinases. Some carboxylic kininogenase sensitive to TASPI was identified in the granulocyte membrane debris fraction. The capability to inhibit neutral kininogenase suggests that TASPI is a first natural proteinase inhibitor, which can differentiate granulocyte and blood plasma kininogenases. Using trypsin-Sepharose 4B in the granulocyte post-granule supernatant, the acid-resistant trypsin and chymotrypsin inhibitor was identified. The data obtained are indicative of an antiinflammatory function of TASPI in mammals.