Table 1 Michaelis–Menten kinetic parameters

From: Gut bacterial tyrosine decarboxylases restrict levels of levodopa in the treatment of Parkinson’s disease

Levodopa

pH 5.0

pH 5.0

pH 4.5

pH 7.4

 

TDCEFS

TDCEFM

PTDCEFM

DDC

[E] (nM)

10

10

10

10

Km (mM)

3 ± 0.4

7.2 ± 0.8

0.4 ± 0.1

0.1 ± 0.01

Vmax (µM/min)

35.3 ± 1.4

25.5 ± 1.3

3.4 ± 0.2

1.4 ± 0.03

Kcat (min−1)

3531 ± 137

2549 ± 133

342.4 ± 21

136.9 ± 3

Kcat/Km (min−1/mM−1)

1160

352

764

1567

R2

0.978

0.99

0.621

0.962

Tyrosine

pH 5.0

pH 5.0

pH 4.5

 
 

TDCEFS

TDCEFM

PTDCEFM

 

[E] (nM)

10

10

10

 

Km (mM)

0.6 ± 0.1

1.5 ± 0.3

0.2 ± 0.05

 

Vmax (µM/min)

69.6 ± 2.9

22 ± 2.5

4.4 ± 0.2

 

Kcat (min−1)

6963 ± 288

2204 ± 247

435.6 ± 19.2

 

Kcat/Km (min−1/mM−1)

12216

1493

2558

 

R2

0.928

0.902

0.589

 
  1. Enzyme kinetic parameters were determined by Michaelis–Menten nonlinear regression model for levodopa and tyrosine as substrates. ± indicates the standard error