Figure 4.

DNA or heparin do not rescue the activity of inactivated tryptase. (A) β-tryptase (0.07 μg) was incubated at 37 °C for 3 h in the absence or presence of either heparin or dsDNA, followed by measurement of residual tryptase activity using S-2288. (B) Human β-tryptase (0.07 μg) was enzymatically inactivated by incubation in the absence of heparin or dsDNA for 3 h (37 °C). After complete inactivation (3 h), tryptase was further incubated for 30 min, either alone or in the presence of either heparin or dsDNA as indicated. Tryptase activity was then measured using the chromogenic substrate S-2288. The data are representative of three independent experiments. Data are given as mean values ± SD (n = 3).