Table 1.

Kinetic parameters Vmax and KM of TNAP phosphatase 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
VmaxKMVmaxKM
08.7 ± 16.1 ± 132 ± 1041 ± 13
207.5 ± 15.8 ± 126 ± 833 ± 11
2002.0 ± 0.1*9.1 ± 3*17 ± 1*19 ± 2*
20001.5 ± 0.3*9.9 ± 5*10 ± 2*11 ± 3*
  • * Calculated value with MPA present is statistically significantly different (p < 0.05) from the value with no MPA.