Enzyme | Inactivator | PR^{b} | k_{2} (s^{−1}) | (k)_{i}_{lim} (s^{−1}) | K (μM)^{c} | K (μM)_{m}^{c} | k_{2}/K (M^{−1} s^{−1}) | (k)_{i}_{lim}/K (M_{m}^{−1} s^{−1}) |
---|---|---|---|---|---|---|---|---|

TEM-1 | NXL104 | — | 0.11 | 0.3 (0.26) | 370,000 | |||

TEM-1 | TZB | >150 | 0.02 | 0.014^{d} (0.030) | 1,400,000 | |||

TEM-1 | CLA | >100 | 0.03 | 0.5^{e} (0.8) | 60,000 | |||

P99 | NXL104 | — | 0.05 | 5.1 (7.7) | 10,000 | |||

P99 | TZB | 11 | 0.15 | 300 (170) | 500 |

↵

*a*Standard deviation of <20% for all the values except as noted.↵

*b*PR, partition ratio. This ratio does not apply (—) to a simple linear scheme where stability of the EI complex results from a*k*_{3}value that is close to zero. If a rearrangement does in fact take place with NXL104 (rate constant*k*_{4}), then the*k*_{3}*/k*_{4}ratio values for both P99 and TEM-1 would be close to zero according to the data shown in Fig. 3a and c. NXL104 obeys scheme 1 with*k*_{3}= 0 (or close to) for both enzymes; TZB and CLA obey the branched-pathway model.↵

*c*The value in parentheses is the*K*value obtained by competition with nitrocefin during a very short incubation (5 s)._{i}↵

*d*Standard deviation of 0.006 μM.↵

*e*Standard deviation of 0.2 μM.