Fibrinolytic and amidolytic activities of elastase-and chymotrypsin-like proteases in spleen and leukocytes of some mammals.

Nonplasmin-mediated fibrinolytic activities were extracted with 2 M NaCIO4 from the spleen and leukocytes of nine species of mammals. The amidolytic and fibrinolytic activities of extracts were measured using Suc-Ala-Tyr-Leu-Val-pNA for elastase-like protease (ELP) and Suc-Tyr-Leu-Phe-pNA (or Suc-Ile-Pro-Phe-pNA) for chymotrypsin-like protease (CLP). ELP and the fibrinolytic activity in the human spleen and leukocytes exhibited the highest values among the nine species. The relative order of amidolysis by CLP was as follows: hamster greater than rat greater than mouse greater than dog in the spleen and hamster greater than rat = ox greater than dog in leukocytes. Neither fibrinolytic nor amidolytic activity was measurable in spleens and leukocytes of pigs and rabbits. The ratios of ELP to CLP activity in the spleen or leukocytes of each of the species varied significantly from those observed in humans. The amidolytic activity of the spleen in control mice was low; however, that of mice which had been intraperitoneally inoculated with sarcoma 180 cells was enhanced and further accompanied by an increase in the number of granulocytes and in fibrinolytic activity. These results suggest that the enhancement of spleen amidolytic and fibrinolytic activities is induced by an increase of granulocytes in the circulation.