Table 1 Kinetic parameters of TyrA enzymes

From: Coordinated regulation of the entry and exit steps of aromatic amino acid biosynthesis supports the dual lignin pathway in grasses

 

Km

kcat

kcat/Km

IC50

Ki

(mM arogenate)

(s−1)

(s−1 · mM−1)

(µM tyrosine)

(µM tyrosine)

BdTyrA1

1.41 ± 0.24

5.2 ± 0.8

3.6 ± 0.8

66 ± 2

46 ± 3

SbTyrA1

0.57 ± 0.15

2.9 ± 0.6

5.3 ± 0.8

71 ± 24

53 ± 10

BdTyrA2

0.45 ± 0.04

18.5 ± 0.6

41.2 ± 1.7

20 ± 6

8 ± 2

SbTyrA2

2.13 ± 0.53

38.5 ± 8.8

18.1 ± 9.6

47 ± 23

36 ± 13

BdTyrAnc

0.13 ± 0.04

76.5 ± 5.5

579.6 ± 24.3

242 ± 45

64 ± 25

SbTyrAnc

0.22 ± 0.06

73.5 ± 18.2

337.5 ± 19.5

406 ± 85

137 ± 44

  1. kcat/Km was calculated based on Km, kcat and the molecular weight of each recombinant enzyme (including the mass of poly-histidine tag). The half-inhibitory concentration of tyrosine (IC50) was calculated at 0.5 mM of arogenate and 1 mM of NADP+ from the data shown in Supplemental Fig. S6. The inhibition constant for tyrosine (Ki) was calculated from Km and IC50 values under a competitive inhibition model19,20. Data represent average ± SD of n = 4−6 derived from at least two independent experiments conducted on different days using different batches of purified recombinant enzyme. Km and kcat were calculated from Michaelis–Menten plots shown in Supplemental Fig. S6.
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