Table 5 Kinetic parameters of M2 (quercetin-3-glucuronide) formation by single expressed UGT1A9*NCFP and double expressed UGT1A9*NCFP/2B7*NHA systems.

From: Inter-isoform Hetero-dimerization of Human UDP-Glucuronosyltransferases (UGTs) 1A1, 1A9 and 2B7 and Impacts on Glucuronidation Activity

1A9*NCFP or 1A9*N/2B7*N

Km (μM)

Ksi (μM)

Vmax (pmol/min/unit)

CLint (μL/min/unit)

% of 1A9*NCFP

1A9*1CFP

7.79 ± 0.34

 

1575 ± 8.08

109.7

100

1A9*1CFP/2B7*1HA

7.78 ± 1.09

 

5102 ± 203.1***

357.0***

325.4

1A9*1CFP/2B7*71SHA

8.16 ± 1.48*

 

2861 ± 158.9***

196.7***

179.3

1A9*1CFP/2B7*2HA

8.22 ± 0.59

 

4175 ± 67.87***

274.3***

250.1

1A9*1CFP/2B7*5HA

2.57 ± 0.25

 

2694 ± 33.12***

1049***

956.8

1A9*2CFP

21.02 ± 6.99

233.0 ± 120.4

175.5 ± 31.82

8.35

100

1A9*2CFP/2B7*1HA

8.17 ± 0.65*

 

194.7 ± 4.05

12.33*

147.6

1A9*2CFP/2B7*71SHA

6.81 ± 1.16*

 

372.0 ± 24.75**

29.59***

354.5

1A9*2CFP/2B7*2HA

7.29 ± 1.59*

251.2 ± 74.53

300.3 ± 25.82*

41.22***

493.7

1A9*2CFP/2B7*5HA

12.75 ± 2.21

209.2 ± 50.92

151.1 ± 12.60

11.85*

141.9

1A9*3CFP

34.39 ± 7.55

139.5 ± 40.24

688.3 ± 96.12

20.01

100

1A9*3CFP/2B7*1HA

77.71 ± 34.34

105.2 ± 59.67

1572 ± 524.9*

20.23

101.0

1A9*3CFP/2B7*71SHA

39.23 ± 11.71

85.86 ± 29.50

788.0 ± 159.7

20.09

100.4

1A9*3CFP/2B7*2HA

7.66 ± 1.60

 

485.4 ± 22.87*

63.37**

316.6

1A9*3CFP/2B7*5HA

6.14 ± 0.52**

 

378.1 ± 5.00*

30.94**

154.6

1A9*5CFP

34.65 ± 9.19

211.5 ± 87.71

448.7 ± 73.77

12.95

100

1A9*5CFP/2B7*1HA

7.13 ± 0.41

 

137.9 ± 0.98**

9.83***

75.9

1A9*5CFP/2B7*71SHA

6.50 ± 0.42*

 

464.5 ± 3.40

35.97***

277.8

1A9*5CFP/2B7*2HA

14.17 ± 3.00*

286.4 ± 99.91

415.5 ± 42.54**

29.32**

226.4

1A9*5CFP/2B7*5HA

9.56 ± 2.79*

 

308.8 ± 36.08*

20.81*

160.7

  1. Asterisks indicate statistically significant differences compared with UGT1A9*NCFP single expression systems (***P < 0.0001, **P < 0.005, *P < 0.05). Data are mean ± SD of three independent determinations.
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