Characterization and primary sequence of a human hepatic microsomal estriol UDPglucuronosyltransferase

Arch Biochem Biophys. 1990 Aug 15;281(1):170-5. doi: 10.1016/0003-9861(90)90428-2.


A human liver microsomal UDP glucuronosyltransferase (UDPGT) that demonstrates reactivity with estriol (pI 7.4 UDPGT) has been purified to homogeneity and characterized further. No activity toward morphine, 4-hydroxybiphenyl, bilirubin, or tripelennamine was observed. The estriol UDPGT shows immunoreactivity with antibodies raised against rat hepatic microsomal 3 alpha- and 17 beta-hydroxysteroid UDPGTs but not with antibodies raised against rat hepatic microsomal p-nitrophenol UDPGT. The NH2-terminal sequence of the purified protein was determined and found to correspond to an identical sequence in the deduced amino acid sequence of a cDNA obtained from a human liver library in lambda gt11 (HLUG4). Sequence analysis revealed that HLUG4 is 2094 bp in length and encodes a protein of 523 amino acids which has a 16 amino acid leader sequence, followed by an untranslated 3' region of 525 bp. Three potential N-glycosylation sites were identified in the predicted sequence. The deduced amino acid sequence of estriol UDPGT showed 82% identity with the deduced amino acid sequence of another human hepatic cDNA (HLUG25), which has been expressed as a UDPGT capable of 6 alpha-hydroxyglucuronidation of hyodeoxycholic acid, strongly suggesting that these proteins are members of the same gene subfamily.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA / analysis*
  • Estriol / metabolism*
  • Glucuronosyltransferase / genetics
  • Glucuronosyltransferase / isolation & purification*
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / isolation & purification*
  • Microsomes, Liver / enzymology*
  • Molecular Sequence Data
  • Restriction Mapping
  • Substrate Specificity


  • Isoenzymes
  • DNA
  • Glucuronosyltransferase
  • Estriol