| Abstract: | Using an inhibitory analysis, the different enzymatic nature of kininogenase and elastase activities in serine proteinase fractions (pI 8.3-10.75) isolated from human granulocyte lysates by isoelectrofocusing was demonstrated. The thermo- and acid-stable serine proteinase inhibitor from rabbit serum was shown to completely inhibit the kininogenase activity in these fractions but to have no inhibiting action on the elastase activity. On the contrast, the specific granulocyte elastase inhibitor, N-3-carbomethoxypropanoyl-L-alanyl-L-alanyl-L-prolyl-L-valyl-chloromethylketone , inhibits granulocyte elastase and does not inhibit the kininogenase activity in lysate fractions. The efficiency of granulocyte elastase inhibition by this chloromethylketone is evaluated by the kinetic parameters k3, Ki. The values of k3/Ki for granulocyte elastase forms with pI of 10.75, 8.9 and 8.0 are 1430, 670 and 360 M-1 S-1, respectively and show effective inhibition of the three forms by this inhibitor. Based on the different degree of inhibition of the three elastase forms by chloromethylketone inhibitor the existence of the family of elastaselike enzymes in human granulocytes is postulated. |
