Table 2.

The effect of various protease inhibitors on CAF

Protease inhibitor	Maximal % reduction of CAF activity*
Antipain	65	99	47
Calpain inhibitor II	0	8
Pefabloc (AEBSF)	79	61	47
Benzamidine	40	0	24
Ecotin (Arg-Met)†	40	36	42
Ecotin (wild type)	5	11
Aprotinin	42	43
α2-Macroglobulin	58

^*The effect of each protease inhibitor on CAF activity was determined as described for leupeptin in the legend of Fig. 1. The maximal inhibitory effect was usually seen at 10–20 ug/ml of the protease inhibitor, with the exception of inhibition by α2-macroglobulin, which was maximal at 100 ug/ml. The range of molar concentrations (in 10-fold increments) tested for each protease inhibitor was as follows: antipain, 0.2–16 μM; calpain inhibitor II, 0.2–25 μM; AEBSF, 0.4–42 μM; benzamidine, 0.6–64 μM; ecotin, 2.6–260 nM; aprotinin, 0.01–1.5 μM; α2-macroglobulin, 1.4–138 nM. The numbers shown for each protease inhibitor were obtained from one to three separate experiments. The values for a given protease inhibitor were obtained by using different CD8⁺ cell fluids. See Table 1 for comparison with effect of leupeptin in several separate studies. 

^† Ecotin (Arg-Met) represents a mutated form of wild-type ecotin with higher antitrypsin activity in which the methionine at position 84 was substituted with an arginine.