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. Author manuscript; available in PMC: 2012 Sep 19.

Published in final edited form as: Chem Res Toxicol. 2011 Aug 5;24(9):1549–1559. doi: 10.1021/tx200178v

Table 3.

Kinetic analysis of glucuronide formation by UGT-over-expressing HEK293 cell lines.

	DB[a,l]P-(+)-trans-11-Gluc^a			DB[a,l]P-(+)-trans-12-Gluc^a			DB[a,l]P-(−)-trans-11-Gluc^b

	K_m (µM)	k_cat (min⁻¹)^c	k_cat/K_m (mM⁻¹.min⁻¹)	K_m (µM)	k_cat (min⁻¹)^c	k_cat/K_m (mM⁻¹.min⁻¹)	K_m (µM)	k_cat (min⁻¹)^c	k_cat/K_m (mM⁻¹.min⁻¹)
UGT1A1	76 ± 21	0.44 ± 0.05	6.1 ± 1.5	78 ± 19	0.23 ± 0.04	3.1 ± 0.6	44 ± 8.0	0.22 ± 0.01	0.72 ± 0.07
UGT1A7	43 ± 7.0	0.009 ± 0.003	0.23 ± 0.11	nd ^d	nd	<0.001	28 ± 1.3	0.005 ± 0.001	0.18 ± 0.03
UGT1A8	194 ± 39	0.15 ± 0.02	0.80 ± 0.12	nd	nd	<0.001	243 ± 52	0.10 ± 0.02	0.46 ± 0.03
UGT1A9	0.17 ± 0.01	0.48 ± 0.04	2980 ± 146	nd	nd	<0.001	0.21 ± 0.05	0.70 ± 0.24	3290 ± 59
UGT1A10	33 ± 9.8	0.30 ± 0.03	9.5 ± 2.0	66 ± 19	0.16 ± 0.01	2.6 ± 0.5	13 ± 1.7	0.17 ± 0.004	13 ± 1.3
UGT2B7	175 ± 25	0.066 ± 0.007	0.38 ± 0.01	nd	nd	<0.001	nd	nd	<0.001

^a

Glucuronides produced from DB[a,l]P-(+)-trans-11,12-diol enantiomer incubated with individual UGTs.

^b

Glucuronide produced from DB[a,l]P-(−)-trans-11,12-diol enantiomer incubated with individual UGTs.

^c

k_cat was adjusted for UGT expression according to Western blot analysis.

^d

nd indicates that glucuronide peaks were not detected, with a sensitivity of 0.8 pmol.