Kinetic parameters Vmax and KM of TNAP pyrophosphatase assay: effect of mercaptopyruvate (MPA). At least 4 sets of experiments in duplicates were performed. Values are mean ± standard deviation.
| MPA, μM | [Ca++] = [Mg++] = 0 mM | [Ca++] = [Mg++] = 1 mM | ||
|---|---|---|---|---|
| Vmax | KM | Vmax | KM | |
| 0 | 20 ± 2 | 35 ± 12 | 56 ± 3 | 126 ± 29 |
| 20 | 20 ± 4 | 31 ± 10 | 52 ± 3 | 133 ± 16 |
| 200 | 15 ± 2.2 | 54 ± 39 | 39 ± 4* | 137 ± 23 |
| 2000 | 12 ± 2.3* | 50 ± 19 | 27 ± 5* | 181 ± 73 |
↵* Calculated value with MPA present is statistically significantly different (p < 0.05) from the value with no MPA.