.UGT1various forms catalyze conjugation of planar phenols, bulky
phenols, amines, tertiary amines, and bilirubin. (Nine active human
forms now cloned are expressed, i.e., 1A1, 1A3–1A10).
.UGT2Aolfactory (nasal) UGTs.
.UGT2Bxenobiotics, steroids and bile acids (4 human active enzymes,
i.e., 2B4, 2B7, 2B10, 2B15, 2B17).
COOH
HO
Etianic acid (C20a,b )
COOH
HO
HO
COOH
Lithocholic acid (3a-OH)
cis ring A/B fusion
HO
COOH
Hyodeoxycholic acid (3a, 6 a -OH)
OH
OH
O
Testosterone (17b-OH)
OH
HO
Androsterone (3a-OH,5a)
H
OH
HO
Estradiol (17 b-OH)
OH
HO
OH
Estriol (16a,-17b-OH)
O
HO Estrone
(3a-OH,5b)
FIGURE 3.4 Structures of endogenous compounds involved in glucuronidation: bile
acids, lithocholic acid (LA) and hyodeoxycholic acid (HDCA); short chain bile acids,
etianic acid and isoetianic acid, steroid hormones, androsterone, testosterone, estrone,
estradiol, estriol.
UDP-GLUCURONOSYLTRANSFERASES 41