Table 1. Screening of serine peptidase inhibitory activity of EgKUs.
| P1a | Trypsinb | Chymotrypsinb | |
|---|---|---|---|
| EgKU-1c | Q | NId | NId |
| EgKU-2 | W | NDe | High |
| EgKU-3 | L | NId | High |
| EgKU-4 | R | Low | NDe |
| EgKU-5 | R | High | NDe |
| EgKU-6 | R | High | NDe |
| EgKU-7 | R | High | NDe |
| EgKU-8c | R | High | Low |
The activity was considered “high” when curvatures were observed in titration assays (initial steady-state rate versus enzyme concentration plots) and the KI* values were < 10−10 M. The activity was considered “low” when titration plots were linear and the KI* values were > 10−9 M. Refer to Fig 1 and the text for further details.
aAmino acid at position 15 (numbering as per mature BPTI), corresponding to the active site of serine peptidase inhibitors.
bThe assays were carried out with cationic trypsin and chymotrypsin A from bovine pancreas.
cData with recombinant EgKU-1 and EgKU-8 reproduced those obtained with the native proteins ([3]; see the text for further details).
dNI, not inhibited.
eND, not determined.