Cloning and Expression of Human UDP-Glucuronosyltransferase (UGT) 1A8

The mRNA expression of human UDP-glucuronosyltransferase 1A8 (UGT1A8) has been found in jejunum, ileum, and colon but not in liver. A cDNA with a complete UGT1A8 coding region was amplified from total human ileal RNA by reverse transcriptase–polymerase chain reaction and inserted into the mammalian expression vector, pcDNA3. Lysates of HK293 cells expressing UGT1A8 revealed the expression of a protein with a molecular mass of 56 kDa by Western blot analysis. Transiently expressed human UGT1A8 shows glucuronidation activities with coumarins, anthraquinones, flavonoids, phenolic compounds, catechol estrogens, 17-hydroxyandrogens, primary amines such as the carcinogen 4-aminobiphenyl, and certain opioids. This UGT may play an important role in the detoxification of xenobiotics in human intestine.