Table 3.
Steady-State Kinetic Parameters with Purified PenA1 and R220A β-Lactamases
| Ki-app (μM) | PenA1 | R220A | fold increase |
|---|---|---|---|
| avibactam | 0.5 ± 0.1 | 13 ± 3 | 26 |
| relebactam | 9 ± 1 | 110 ± 17 | 12 |
| clavulanic acid | 5 ± 1 | 26 ± 3 | 5 |
| tazobactam | 0.6 ± 0.1 | 36 ± 10 | 60 |
| enmetazobactam | 1.1 ± 0.3 | 24 ± 5 | 22 |
| vaborbactam | 38 ± 4 | 108 ± 10 | 3 |
| k2/K (M−1 s−1) | PenA1 | R220A | fold decrease |
| avibactam | 2 ± 1 × 106 | 5.2 ± 0.1 × 103 | 385 |
| relebactam | 1.1 ± 0.2 × 104 | 2.3 ± 0.8 × 102 | 48 |
| clavulanic acid | 6.3 ± 0.1 × 103 | 3.4 ± 0.2 × 103 | 1.9 |
| tazobactam | 1.3 ± 1.0 × 105 | 3.2 ± 0.4 × 103 | 41 |
| enmetazobactam | 6.3 ± 2.0 × 105 | 8.1 ± 1.5 × 103 | 77 |
| vaborbactam | 3.4 ± 0.1 × 102 | 8.4 ± 2.0 × 101 | 4 |
| tn (15 min) | PenA1 | R220A | fold decrease |
| avibactam | 5 | 10 | 2b |
| relebactam | 10 | 50 | 5b |
| clavulanic acid | 5000 | 2000 | 2.5 |
| tazobactam | 50 | 10 | 5 |
| enmetazobactam | 100 | 10 | 10 |
| vaborbactam | 200a | 100a | 2 |
a
Represents the stoichiometry of inactivation, as vaborbactam does not undergo side reactions or hydrolysis.
b
The represented fold change values are increased not decreased for the DBOs.