Table 1.
Steady-state kinetic parameters for the activities of Gsps and its mutants
| GspS/mutant | Km, GSH (μM) | Km, spermidine (μM) | kcat/s |
|---|---|---|---|
| Wild type | 218±12 | 76±1 | 4.35±0.30 |
| C338A | 2098±152 | 406±38 | 4.28±0.35 |
| S335A | 794±71 | 126±15 | 3.31±0.17 |
| S337A | 224±3 | 76±3 | 2.49±0.21 |
| R538A | 1324±34 | 182±37 | 1.01±0.19 |
| T441A | 691±100 | 1610±137 | 0.25±0.05 |
| K607A | 251±29 | 153±14 | 4.55±0.19 |
| E392A | 7298±701 | 1008±92 | 0.75±0.05 |
| E391A | 407±42 | 4522±107 | 0.43±0.01 |
| R598A | 22.4±0.52 | 665±76 | 0.29±0.02 |
| R316E | —a | —a | —a |
| Values were determined by a previously reported spectrometric assay (see Materials and methods), which involved titration of a variable substrate in the presence of saturating concentrations of the other two substrates. | |||
| Not detected. |