Table 2

Apparent kinetic parameters for glucuronidation of LA, 13-HODE, and 13-OXO by human liver microsomes

SubstrateEnzyme SourceKmVmaxVmax/ Km
μM nmol/mg·min μl/mg·min
Linoleic acid2-a 2-b
HLM18146 ± 155.29 ± 0.3236.6 ± 3.3
UGT2B7124 ± 19.52.78 ± 0.0125.0 ± 8.8
13-OXO2-c
HLM22-d 916.3669.8
UGT2B72-e 32,121.1,1.0234.4,83.3
13-HODE
 COOH2-b HLM22-d 3485.0322.1
 OH2-f 641.2518.6
 COOH2-b 2-d UGT2B7261.30500.0
 OH2-e 2-f 75,70.8,0.410.7,57.1

Apparent Km and Vmax values were determined with 25 to 300 μM substrate at a constant concentration (4 mM) of UDPGlcUA. Results are expressed as the mean of two determinations, the mean ± S.D. of at least four determinations, or two individual determinations with two different UGT2B7 membrane preparations.

  • ↵2-a  Mean ± S.D. of at least four determinations.

  • ↵2-b  Carboxyl-linked glucuronide.

  • ↵2-c  Glucuronide structure not determined.

  • ↵2-d  Mean of two determinations.

  • ↵2-e  Two individual determinations.

  • ↵2-f  Hydroxyl-linked glucuronide.