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Table 1 Kinetic constants of the alkaliphilic variants derived from RY2 laccase for the oxidation of different substrates

From: Tailor-made alkaliphilic and thermostable fungal laccases for industrial wood processing

Laccase (mutations)

Substrate

pH

kcat (s−1)

Km (mM)

kcat/Km (mM−1 s−1)

RY2 (parent)

ABTS

3

543 ± 17

0.01 ± 0.001

52,240 ± 569

 

DMP

5

123 ± 6

0.26 ± 0.04

479 ± 76

 

DMP

8

Undeterminable -

  

Li10 (F392N, F396I, F460M)

ABTS

3

231 ± 5.6

1.3 ± 0.1

179 ± 16

 

DMP

8

89 ± 6.2

20 ± 2.4

4 ± 0.6

 

DMP

9

9.5 ± 0.1

1.1 ± 0.03

9 ± 0.1

Li11 (D263V, F392N, F396I, F460M)

ABTS

3

123 ± 5.5

0.5 ± 0.04

266 ± 26

 

DMP

8

82 ± 7.6

1.5 ± 0.1

55 ± 6.7

 

DMP

9

22 ± 1.3

0.3 ± 0.03

72 ± 8.5

 

DMP

10

0.8 ± 0.03

0.027 ± 0.001

29 ± 1.5

C-LeB (D263V, F392N, F396I, A458L, F460M)

ABTS

3

136 ± 2.7

0.7 ± 0.04

200 ± 12

 

DMP

8

42 ± 1.3

1.7 ± 0.1

25 ± 1.6

 

DMP

9

26 ± 0.3

0.4 ± 0.01

61 ± 1.6

 

DMP

10

2 ± 0.05

0.022 ± 0.002

95 ± 9

Mol3 (D263V, F392N, F396I, V424T, S429T, D441N A458L, F460M)

ABTS

3

113 ± 1.8

0.9 ± 0.02

125 ± 3.4

 

DMP

8

63 ± 1.8

1.7 ± 0.2

37 ± 4.4

 

DMP

9

16 ± 1.2

0.3 ± 0.02

53 ± 5.3

 

DMP

10

0.7 ± 0.01

0.019 ± 0.001

37 ± 1.9

  1. Kinetics for the oxidation of DMP as a lignin-derived phenol at alkaline pH and of ABTS (as a reference of laccase intrinsic acidic activity) by selected alkaliphilic and thermal-tolerant variants obtained by directed evolution of RY2 laccase. Mutations accumulated in the evolved variants are shown in brackets.