Kinetic parameters determined for four arginine kinase (AK)constructs: Ensis full-length AK, D2—NusA—His-tag fusion protein, D2 alone and Limulus AKWTrev
| Parameter . | Ensis full-length . | Ensis D2—NusA—His-tag . | Ensis D2 . | Limulus WT . |
|---|---|---|---|---|
| Arginine phosphate | ||||
| Kia (mmol l-1) | 0.333±0.046 | 0.618±0.083 | 0.592 (0.578, 0.606) | 0.804±0.038 |
| Ka (mmol l-1) | 0.313±0.059 | 1.222±0.166 | 0.645 (0.625, 0.665) | 0.226±0.004 |
| Kia/Ka | 1.06 | 0.51 | 0.92 | 3.56 |
| ADP | ||||
| Kia (mmol l-1) | 0.050±0.008 | 0.087±0.012 | 0.076 (0.078, 0.074) | 0.156±0.010 |
| Ka (mmol l-1) | 0.053±0.003 | 0.160±0.009 | 0.086 (0.084, 0.087) | 0.043±0.002 |
| Kia/Ka | 0.94 | 0.54 | 0.88 | 3.62 |
| Vmax (μmol min-1 mg-1) | 196.65±17.41 (D2 only: 391.79) | 175.57±7.45 (D2 only: 434.50) | 446.07 (460.48, 431.65) | 223.32±8.09 |
| Kcat (s-1) | 266.31 | 295.33 | 303.21 | 156.32 |
| Parameter . | Ensis full-length . | Ensis D2—NusA—His-tag . | Ensis D2 . | Limulus WT . |
|---|---|---|---|---|
| Arginine phosphate | ||||
| Kia (mmol l-1) | 0.333±0.046 | 0.618±0.083 | 0.592 (0.578, 0.606) | 0.804±0.038 |
| Ka (mmol l-1) | 0.313±0.059 | 1.222±0.166 | 0.645 (0.625, 0.665) | 0.226±0.004 |
| Kia/Ka | 1.06 | 0.51 | 0.92 | 3.56 |
| ADP | ||||
| Kia (mmol l-1) | 0.050±0.008 | 0.087±0.012 | 0.076 (0.078, 0.074) | 0.156±0.010 |
| Ka (mmol l-1) | 0.053±0.003 | 0.160±0.009 | 0.086 (0.084, 0.087) | 0.043±0.002 |
| Kia/Ka | 0.94 | 0.54 | 0.88 | 3.62 |
| Vmax (μmol min-1 mg-1) | 196.65±17.41 (D2 only: 391.79) | 175.57±7.45 (D2 only: 434.50) | 446.07 (460.48, 431.65) | 223.32±8.09 |
| Kcat (s-1) | 266.31 | 295.33 | 303.21 | 156.32 |
With the exception of Ensis D2, all kinetic parameters are given as a mean value of at least three kinetic runs ± S.D. Ensis D2 values are given as a mean of two kinetic runs, with values from each run given in parentheses. Values shown in bold are Vmax values for Ensis full-length AK and D2—NusA—His-tag fusion protein if only the mass of D2 is taken into consideration.