TABLE 2.
Catalytic activity of rSso0417a
| Activity type (enzyme) | Substrate | Concn (mM) | Cofactor | Temp (°C) | Mean reaction rate (μmol/min/mg) ± SE |
|---|---|---|---|---|---|
| PGA mutase | 3-PGA | 15 | Mn2+ | 25 | 0.182 ± 0.045 |
| 3-PGA | 15 | Co2+ | 25 | 0.515 ± 0.032 | |
| 3-PGA | 15 | Cd2+ | 25 | 0.113 ± 0.018 | |
| 3-PGA | 15 | Mn2+ + Mg2+ | 25 | 0.165 ± 0.004 | |
| Phosphatase | 3-PGA | 15 | Mn2+ | 65 | 0.017 ± 0.001 |
| 3-PGA | 15 | Co2+ | 65 | 0.050 ± 0.002 | |
| ATP | 2.5 | Mn2+ | 65 | 0.018 ± 0.009 | |
| ATP | 2.5 | Co2+ | 65 | 0.067 ± 0.056 |
a
Shown are the results of steady-state analyses of the rates at which rSso0417, 40 μg per assay, catalyzed conversion of 3- to 2-PGA or the hydrolysis of 3-PGA and ATP. The temperatures of the assays of PGA mutase activity were dictated by the stability of the coupling enzyme, enolase. The temperature of the phosphohydrolase assays was raised to 65°C in order to increase reaction rates to more readily detectable levels. Shown are the results of triplicate determinations. All metal ions were present at a concentration of 5 mM. For further details, see Materials and Methods.