Table 2.
Ki values for chagasin against T. cruzi cruzipain and human cathepsin L
| Substitution |
Region |
Cruzipain |
Cathepsin L |
|---|---|---|---|
| Ki(pM) | |||
| Chagasin | – | 7.6 ± 0.67 | 7.3 ± 1.2 |
| W93A | L6 | 31 ± 3.5 | 825 ± 79 |
| Y89S | β7-strand | 25 ± 3.1 | ND |
| Y89F | β7-strand | 20 ± 0.8 | ND |
| P30A | L2 | 20 ± 1.7 | 45 ± 7.3 |
| T31A | L2 | 317 ± 26 | 3.9 ± 0.7 |
| T31V | L2 | 70 ± 4.3 | 9.7 ± 1.1 |
| T31S | L2 | 11 ± 0.6 | 4.9 ± 0.6 |
| T31Y | L2 | 747 ± 44 | 6.8 ± 0.9 |
| T32A | L2 | 16 ± 1.1 | 14 ± 1.8 |
| T32S | L2 | 20 ± 1.9 | 32 ± 2.2 |
| T32E | L2 | 11 ± 2.0 | ND |
| T32Y | L2 | 16 ± 0.7 | 2.7 ± 0.2 |
| T32V | L2 | 193 ± 13 | 20 ± 0.8 |
| T31A/T32A | L2 | 1065 ± 116 | 1.8 ± 0.4 |
| ΔT31–T32 | L2 | 5868 ± 29 | 2200 ± 17 |
Equilibrium constants for dissociation (Ki) of complexes between cysteine peptidases and chagasin variants. The results are represented as mean values from three independent Ki measurements. The enzymes were assayed for inhibition as described in methods. N.D., not determined. The values are mean of three independent Ki determinations ± S.E. The conditions of hydrolysis: 50 mM Na2HPO4, 100 mM NaCl, 5 mM EDTA, pH 6.5, 5% DMSO, 2.5 mM DTT, at 28 °C.