Table 1.
The catalytic efficiency of PKA Cα mutants for serine and threonine substrates. kcat and KM values were determined using a spectrophotometric kinase assay (Figure S1). The values are represented as means of at least three independent measurements with standard deviation (SD).
| PKA Cα | Substrate | kcat (s−1) | KM (µM) | kcat/KM (×105 M−1s−1) |
|---|---|---|---|---|
| Wt | S-Kemptide | 19.8 ± 1.0 | 19.8 ± 3.9 | 10.3 ± 1.7 |
| T-Kemptide | 7.5 ± 0.8 | 861 ± 184 | 0.09 ± 0.02 | |
| F187V | S-Kemptide | 35.7 ± 0.7 | 81.3 ± 27.1 | 4.8 ± 1.6 |
| T-Kemptide | 39.2 ± 3.7 | 31.5 ± 16.0 | 11.3 ± 4.0 | |
| F187I | S-Kemptide | 25.4 ± 5.8 | 92.2 ± 3.8 | 2.8 ± 0.8 |
| T-Kemptide | 43.0 ± 4.7 | 19.8 ± 3.3 | 22.1 ± 4.5 | |
| F187T | S-Kemptide | 15.7 ± 0.3 | 23.0 ± 3.1 | 6.9 ± 1.2 |
| T-Kemptide | 37.1 ± 4.5 | 25.0 ± 3.4 | 14.9 ± 0.6 |