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Table 1 Kinetic parameters of Zea mays tryptophan synthase and comparison with characterized homologs.

From: Characterisation of the tryptophan synthase alpha subunit in maize

Reaction

Recombinant Enzyme(s)

Substrate

KM (μM)

kcat (s-1)

kcat/KM(mM-1 s-1)

α

ZmTSA

IGP

458 ± 94

0.006 ± 0.002

0.013

α

ZmTSA+ZmTSB1

IGP

52 ± 6

0.019 ± 0.004

0.37

β

ZmTSB1

Indole

24 ± 4

0.29 ± 0.04

12.1

β

ZmTSA+ZmTSB1

Indole

28 ± 6

0.44 ± 0.07

15.7

αβ

ZmTSA+ZmTSB1

IGP

47 ± 9

0.45 ± 0.06

9.6

α

ZmTSAlike

IGP

n. d.

n. d.

n. d.

α

ZmTSAlike+ZmTSB1

IGP

n. d.

n. d.

n. d.

α

BX1 [18]

IGP

13

2.8

215

α

IGL [17]

IGP

100

2.3

23

α

EcTSA 1)

IGP

480

0.002

0.004

α

EcTSA + EcTSB 1)

IGP

27

0.2

7.4

α

StTSA + StTSB 2)

IGP

100

0.14

1.4

β

StTSA + StTSB 2)

Indole

15

3.6

240

αβ

StTSA + StTSB 2)

IGP

20

3

150

  1. 1) [31], Ec: E. coli.
  2. 2) [35], St: S. typhimurium.
  3. n. d.: For ZmTSAlike no IGP turnover was detected.