Table 4 Kinetic parameters of M1 (quercetin-7-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*N or 1A9*N/2B7*N Km (μM) Vmax (pmol/min/unit) CLint (μL/min/unit) % of 1A9*NCFP
1A9*1CFP 14.99 ± 0.88 1868 ± 35.67 69.43 100
1A9*1CFP/2B7*1HA 10.64 ± 1.86* 4469 ± 301.4*** 258.7*** 372.6
1A9*1CFP/2B7*71SHA 10.03 ± 0.63** 2567 ± 31.33*** 130.4*** 187.8
1A9*1CFP/2B7*2HA 11.20 ± 1.75* 4505 ± 159.9*** 402.2*** 579.3
1A9*1CFP/2B7*5HA 9.82 ± 0.93** 2334 ± 48.23** 237.7*** 342.4
1A9*2CFP 15.58 ± 1.82 263.7 ± 8.304 16.93 100
1A9*2CFP/2B7*1HA 9.82 ± 1.72* 164.1 ± 4.60*** 16.71 98.7
1A9*2CFP/2B7*71SHA 8.99 ± 0.99* 275.3 ± 6.90 30.62*** 180.9
1A9*2CFP/2B7*2HA 9.00 ± 0.95* 186.1 ± 4.50** 20.67** 122.1
1A9*2CFP/2B7*5HA 6.43 ± 0.79** 76.13 ± 1.92*** 11.84** 69.9
1A9*3CFP 48.11 ± 6.05 600.7 ± 29.61 12.49 100
1A9*3CFP/2B7*1HA 28.72 ± 1.97 1029 ± 27.56*** 19.36*** 155.0
1A9*3CFP/2B7*71SHA 28.97 ± 11.27 553.5 ± 63.25 19.11* 153.0
1A9*3CFP/2B7*2HA 35.30 ± 5.91 1068 ± 64.32** 30.25*** 242.2
1A9*3CFP/2B7*5HA 25.24 ± 2.74 746.6 ± 31.95** 16.59** 132.8
1A9*5CFP 22.41 ± 1.99 408.7 ± 10.99 18.24 100
1A9*5CFP/2B7*1HA 13.56 ± 1.35** 146.5 ± 3.78*** 10.80*** 59.2
1A9*5CFP/2B7*71SHA 15.56 ± 1.31* 480.9 ± 10.96** 30.91*** 169.5
1A9*5CFP/2B7*2HA 11.19 ± 1.29** 316.7 ± 8.91** 28.30*** 155.2
1A9*5CFP/2B7*5HA 26.30 ± 5.25 263.2 ± 16.72** 10.01*** 54.9
  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.