Table 2. Kinetic parameters of drDDC WT and mutant proteins towards different substrates.
| KM mM | k cat min−1 | k cat /KM min−1mM−1 | ||
| Dopa | ||||
| WT | 2.2±0.3 | 282±1.6 | 128.2 | |
| T82A | 5.6±1 | 524±44.2 | 93.6 | |
| T82S | 4.5±0.9 | 672.6±61.9 | 149.5 | |
| H192W | 4.4±0.8 | 93.2±9.7 | 21.2 | |
| m-tyr | ||||
| WT | 2.3±1.2 | 213.8±40.4 | 93 | |
| T82A | 13.3±4.5 | 859.8±179 | 64.6 | |
| T82S | 11.4±2.2 | 690.5±80.2 | 60.6 | |
| H192W | 2.6±1.1 | 63.5±9.6 | 24.4 | |
| o-tyr | ||||
| WT | 1.1±0.3 | 110.8±8 | 100.7 | |
| T82A | 4.9±1.5 | 319.9±43 | 65.3 | |
| T82S | 1.9±0.7 | 225.7±28.2 | 118.8 | |
| H192W | 1.9±0.4 | 38.7±2.5 | 20.4 | |
| 5-HTP | ||||
| WT | 0.4±0.04 | 62.8±1.4 | 157 | |
| T82A | 3.5±0.5 | 440.4±23.4 | 125.8 | |
| T82S | 0.6±0.1 | 102.6±3 | 171 | |
| H192W | 1.1±0.1 | 32.4±0.8 | 29.4 | |
The activities were measured as described in Materials and Methods. The KM and k cat for different substrates were derived by using varying concentrations (0.1 to 12 mM)) of individual substrates. The parameters were calculated by fitting the Michaelis–Menten equation to the experimental data using the enzyme kinetics module. Results are means ± SE.