Table 1 Enzyme kinetic parameters for the sugar transfer of OsUGT91C1 and the mutants.

From: Catalytic flexibility of rice glycosyltransferase OsUGT91C1 for the production of palatable steviol glycosides

Substrate

Enzyme

kcat (min−1)

Km (μM)

kcat/Km (s−1 M−1)

Fold

Rubu

WT

2.0 ± 0.1

49.5 ± 5.3

673

1

(Combined β (1–2)

F208M

2.4 ± 0.1

20.9 ± 1.7

1914

2.8

at R1 and R2)

H93W

1.3 ± 0.1

56.8 ± 8.5

381

0.6

F379A

2.7 ± 0.1

16.5 ± 2.8

2727

4.1

H93W/F208M

1.8 ± 0.1

43.6 ± 5.4

688

1.0

F379A/F208M

2.8 ± 0.1

11.7 ± 1.0

3989

5.9

S13G

WT

2.9 ± 0.1

24.9 ± 2.5

1941

1

(β (1–2) at R1)

F208M

3.9 ± 0.1

18.7 ± 1.7

3476

1.8

H93W

3.9 ± 0.1

36.2 ± 4.7

1796

0.9

F379A

5.8 ± 0.2

19.0 ± 2.6

5088

2.6

H93W/F208M

3.5 ± 0.1

29.1 ± 2.2

2005

1.0

F379A/F208M

3.5 ± 0.1

9.7 ± 1.9

6014

3.1

Reb A

WT

1.22 ± 0.02

45.7 ± 3.0

445

1

(β (1–2) at R2)

F208M

2.9 ± 0.1

25.2 ± 2.0

1918

4.3

H93W

0.60 ± 0.03

58 ± 12

172

0.4

F379A

1.16 ± 0.02

37.0 ± 2.5

523

1.2

H93W/F208M

2.05 ± 0.03

63.9 ± 3.6

535

1.2

F379A/F208M

1.7 ± 0.1

15.1 ± 2.6

1876

4.2

STB

WT

0.63 ± 0.03

71 ± 12

148

–

(β (1–6) at R1)

H93W

ND

–

–

–

F379A

ND

–

–

–

H93W/F208M

ND

–

–

–

F379A/F208M

ND

–

–

–

  1. WT wild type, ND non-detectable, fold fold change over the kcat/Km of the wide type for each substrate.
  2. Assays were performed as described in Methods section. Nonlinear fitting values ±SD (n = 3) are shown. Source data are provided as a Source Data file.
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