TABLE 2.
Kinetic and thermodynamic parameters for the interaction of TLM with KasA and KasB
| Enzyme | IC50 | Kda | Kib | k1b | k2b | Ki*c |
|---|---|---|---|---|---|---|
| μm | μm | μm | s−1 | s−1 | μm | |
| Apo-KasA | 242 ± 60d | 226 ± 9 | NDe | ND | ND | ND |
| Acyl-KasA | 19.0 ± 2.3f | ND | 163 ± 28 | 0.19 ± 0.02 | 0.0004 ± 0.0009 | 0.3 ± 0.8 |
| C171Q KasA | ND | ND | 126 ± 16 | 0.046 ± .002 | 0.0008 ± 0.0005 | 2.2 ± 1.6 |
| Apo-KasB | ND | ≥400 | ND | Rapid | Rapid | Rapid |
| Acyl-KasB | ND | 53 + 5 | ND | Rapid | Rapid | Rapid |
a Kd values were determined by fluorescence titration and fitting the data to the Scatchard equation.
b Parameters were determined by fitting the kobs data for the slow binding of TLM using Equation 2.
c Ki* was calculated using Equation 3.
d IC50 value was determined by preincubating TLM with KasA and malonyl-AcpM and initiating the reaction by the addition of palmitoyl-AcpM.
e ND, not determined.
f IC50 value was determined by preincubating TLM with KasA and palmitoyl-AcpM and initiating the reaction by the addition of malonyl-AcpM.