Table 1. Kinetic constants and arginine inhibition properties (IC50) of NAGK-wt or NAGK‑FL25‑C in the absence or presence of various PII variants.
| NAGK | PII | Km (mM) | Kcat (s-1) | Kcat/Km (s-1 M-1) | IC50 Arg (µM) |
|---|---|---|---|---|---|
| NAGK-wt | - | 3.2 ± 0.1 | 38.8 ± 0.5 | 1.2E+04 | (20) |
| NAGK‑FL25‑C | - | 3.0 ± 0.2 | 41.36 ± 0.5 | 1.4E+04 | 11 ± 1 |
| NAGK-wt | PII-wt | 0.7 ± 0.1 | 119.4 ± 1.6 | 1.8E+05 | 502 ± 20 |
| NAGK‑FL25‑C | PII-wt | 0.5 ± 0.0 | 128.5 ± 0.9 | 2.4E+05 | n.d. |
| NAGK-wt | PII-ST‑V | 0.7 ± 0.0 | 122.8 ± 1.0 | 1.8E+05 | n.d. |
| NAGK‑FL25‑C | PII-ST‑V | 0.6 ± 0.0 | 134.2 ± 1.0 | 2.1E+05 | 561 ± 32 |
| NAGK-wt | PII49G‑ST‑V | 0.5 ± 0.0 | 96.76 ± 1.3 | 1.9E+05 | n.d. |
| NAGK‑FL25‑C | PII49G‑ST‑V | 0.4 ± 0.0 | 99.61 ± 1.0 | 2.5E+05 | 170 ± 21 |
Original data and fitting to determine kinetic constants as well as IC50 Arg is shown in Figure S1. Km and Kcat values ± standard error. IC50 Arg ± 95% confidence interval. n.d., not determined.