TABLE 2.
Comparison of molecular and kinetic properties of cPGIs from P. furiosus, A. fulgidus, M. mazei, S. enterica serovar Typhimurium, E. meliloti, and T. litoralis
| Parameter | Propertya of:
|
|||||
|---|---|---|---|---|---|---|
| PfcPGI* (22) | AfcPGI (This work) | MmcPGI (This work) | StcPGI (This work) | EmcPGIA (This work) | TlcPGI* (30) | |
| Standard assay temp (°C) | 80 | 50 | 37 | 37 | 50 | 50 |
| Apparent molecular mass (kDa) | ||||||
| Native enzyme | ||||||
| Gel filtration | 43 | 28 | 28 | 67 | 43 | 39 |
| Analytical ultracentrifugation | - | 27 | - | - | - | - |
| Subunit (SDS-PAGE) | 20 | 28 | 28 | 32 | 27 | 26.7 |
| Subunit (calculated) | 21.476 | 27.424 | 30.209 | 26.834 | 34.684 | 26.7 |
| Oligomeric structure | α2 | α | α | α2 | α2 | α2 |
| pH optimum | 7.0 | 7.4 | 7.6 | 7.2 | 7.4 | - |
| Temp optimum (°C) | >99 | 82 | 57 | 55 | 57 | - |
| Arrhenius activation energy (kJ/mol) | 50 | 71 ± 3 | 72 | 88 | 41 | - |
| Linear part of Arrhenius plot (°C) | 20-96 | 30-83 | 30-55 | 35-55 | 27-40 | - |
| Tm (°C) | >100* | 97 | 66 | 64 | 58 | - |
| Km (mM) | ||||||
| F6P | 1.0 | 0.6 | 0.7 | 3 | 0.8 | 1.7 |
| G6P | 2.9* | 0.6 | 1.0 | 1.0 | 0.4 | 11.7 |
| Vmax (U/mg) | ||||||
| F6P | 800 | 30 | 2.6 | 0.5 | 0.3 | 72.6 |
| G6P | 130 | 8.5 | 2.4 | 1.5 | 0.5 | 45.5 |
| Ki (mM) | ||||||
| Erythrose-4-phosphate | 3.9* | ND | 1.8 | ND | 1.8 | - |
| 6-Phosphogluconate | 0.30* | 0.67 | 0.15 | 3.0 | ND | 0.38 |
| Sorbitol-6-phosphate | 0.19* | 0.7 | 0.03 | 0.36 | 0.54 | - |
| Mannose-6-phosphate | ND* | ND | ND | ND | ND | 2.3 |
a
*, New data; ND, not detectable; -, not measured. The reference or source is indicated in parentheses in the subheading. F6P, fructose-6-phosphate; G6P, glucose-6-phosphate.