Table 1. Catalytic parameters of wild-type alanine racemase and its mutants.
Enzyme | kcat (s-1) | Rel. kcat | KM (mM) | kcat/KM (M-1s-1) | Rel. kcat/KM |
---|---|---|---|---|---|
wild type | 3.5 (0.1) × 103 | 1 | 2.2 | 1.6 (0.2) × 106 | 1 |
H166Ta | 1.7 (0.1) × 101 | 0.005 | 0.5 | 3.3 (0.2) × 104 | 0.02 |
H166Mh | 8.4 (0.3) × 100 | 0.002 | 0.5 | 1.8 (0.2) × 104 | 0.01 |
H200Ta | 1.2 (0.5) × 101 | 0.003 | 1.6 | 7.3(0.8) × 103 | 0.005 |
H200Mh | 5.2 (0.2) × 100 | 0.002 | 1.6 | 3.2 (0.4) × 103 | 0.002 |
H127Ta | 1.2 (0.4) × 101 | 0.003 | 1.2 | 1.0 (0.1) × 104 | 0.006 |
H127Mh | 2.2 (0.1) × 101 | 0.006 | 1.8 | 1.2 (0.2) × 104 | 0.007 |
H125Ta | 4.1 (0.2) × 103 | 0.8 | 4.7 | 8.7 (0.4) × 105 | 0.5 |
H125A | 4.4 (0.2) × 102 | 0.08 | 0.5 | 8.2 (0.4) × 105 | 0.5 |
H166A | 3.5 (0.2) × 100 | 0.001 | 1.6 | 2.2 (0.3) × 103 | 0.001 |
H166F | 3.9 (0.1) × 100 | 0.001 | 3.9 | 1.0 (0.1) × 103 | 0.0006 |
H127A/H166A/H200A | 2.8 (0.4) × 10-1 | 0.00008 | 0.8 | 3.6(0.5) × 102 | 0.0002 |