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. 2011 Jan 10;156(3):1087–1100. doi: 10.1104/pp.110.164756

Table II. Kinetics parameters of r-PAPhy enzymes.

The specific activities were determined at 36°C, pH 5.0. r-TaPAPhy_b1 and phytate were used for reference. All data were determined in triplicate.

Substrate and Protein Km Vmax kcat kcat/Km
μm μmol min−1 mg−1 s−1 ×104 s−1m−1
Phytate
 r-TaPAPhy_a1 35 ± 6.8 223 ± 9.4 279 796
 r-TaPAPhy_b1 45 ± 3.4 216 ± 12.4 270 600
 r-HvPAPhy_a 36 ± 4.2 208 ± 6.8 260 722
 r-HvPAPhy_b2 46 ± 7.3 202 ± 9.9 253 550
 r-ZmPAPhy_b 48 ± 6.9 198 ± 13.5 248 517
 r-OsPAPhy_b 54 ± 8.2 185 ± 11.7 231 428
r-TaPAPhy_b1
 p-NPP 1,917 ± 32.5 496 ± 11.0 620 32.34
 Fru-1,6-bisP 921 ± 21.8 36 ± 3.5 45 4.89
 Phosphoenolpyruvate 1,793 ± 33.4 256 ± 8.4 320 17.85
 Glycerol-1-phosphate 1,650 ± 42.1 653 ± 14.3 816 49.47
 Pyrophosphate 343 ± 12.8 22 ± 3.1 28 8.13
 Glc-6-P 2,675 ± 64.3 22 ± 7.2 28 1.04
 Fru-1-P 2,314 ± 54.7 24 ± 4.4 31 1.33
 Phospho-Ser 2,560 ± 48.2 15 ± 2.2 19 0.75
 Adenosine triphosphate 1,046 ± 132.3 111 ± 4.2 139 13.26
 Adenosine diphosphate 1,377 ± 142 66 ± 3.2 83 6.03
r-TaPAPhy_b1, phytate control 100%
Pyridoxal-5-phosphate 6% ± 1.2%
ortho-Carboxyphenyl phosphate 45% ± 4.6%
Naphthyl phosphate 68% ± 7.4%
Adenosine monophosphate 11% ± 2.6%
Guanosine triphosphate 210% ± 7%
Fru-6-P Not detectable