Table 1. Summary of nitrocefin and CCF2 assay parameters, including IC50 values for the positive control inhibitor 2-(2-chlorobenzyl) succinic acid (NSC-20707).
| Enzyme | Format | KM(a), μM | [Enzyme], nM | [Substrate], μM | NSC 20707 IC50(b), μM | S/B(c) | Z′(d) |
|---|---|---|---|---|---|---|---|
| VIM-2 | Nitrocefin | 30 ± 9 | 0.13 | 60 | 33 ± 9 | 3.2 ± 0.1 | 0.75 ± 0.1 |
| IMP-1 | Nitrocefin | 29 ± 4 | 0.1 | 60 | 1.6 ± 0.3 | 3.5 ± 0.1 | 0.81 ± 0.03 |
| VIM-2 | CCF2 | 21 ± 7 | 0.1 | 10 | 50 ± 18 | 4.0 ± 0.1 | 0.79 ± 0.09 |
(a)
KM values calculated for IMP-1 and VIM-2 assays ± error reported as the standard deviation of 3 replicates. Reported values for VIM-2 with Nitrocefin is 18 μM11 and IMP-1 with Nitrocefin is 27 μM 56.
(b)
IC50 ± error reported as the standard deviation of 16 replicates.
(c)
S/B ± error reported as the standard deviation of 24 replicates. The signal to basal (S/B) is defined as the ratio of raw signals from wells with positive and negative controls.
(d)
Z′ ± error reported as the standard deviation of 24 replicates. Z'-factor is a measure of assay quality and was calculated according to 32.