Characterization of a cloned human dihydrotestosterone/androstanediol UDP-glucuronosyltransferase and its comparison to other steroid isoforms

Biochemistry. 1993 Oct 12;32(40):10648-57. doi: 10.1021/bi00091a015.


A human cDNA, UDPGTh-3, encoding a dihydrotestosterone/5 alpha-androstane-3 alpha,17 beta-diol UDP- glucuronosyltransferase (transferase) has been isolated and characterized. The nucleotide sequence of UDPGTh-3 encodes a 530 amino acid protein with a typical membrane insertion-signal peptide, a membrane-anchoring domain, and three potential asparagine-linked glycosylation sites. Alignment shows that this encoded isozyme is 96% identical to an apparent estriol-metabolizing isoform, HLUG4 [Coffman, B. L., et al., (1990) Arch. Biochem. Biophys. 281, 170-175]. The udpgth-3 isozyme is 78% identical to two other steroid isoforms, HLUG25 (udpgth-1) [Jackson, M. R., et al. (1987) Biochem. J. 242, 581-588; Ritter, J. K., et. al. (1992) Biochemistry 31, 3409-3414] and udpgth-2 [Ritter, J. K., et al. (1990) J. Biol. Chem. 265, 7900-7906]. udpgth-2 and udpgth-1 metabolized parallel substrates (stereospecific estriols, 3,4-catechol estrogens, and the bile salt hyodeoxycholate), except that udpgth-2 was 100-fold more effective than udpgth-1. The mRNA encoding udpgth-3 is 2.4 kb in size and is present in liver, prostate, and testis; the mRNA encoding udpgth-2 is located in liver and kidney, whereas that for udpgth-1 is liver-specific. Each of the liver mRNA species encoding udpgth-3, udpgth-2, or udpgth-1 was induced 2.5-3-fold by phenobarbital treatment of the Erythrocebus patas monkey. In 16 human liver mRNA samples, the message encoding udpgth-3 was generally uniformly expressed and that for udpgth-1 exhibited wide variations in its level, whereas that for udpgth-2 was barely detectable in nine samples and not detectable in the others. Three samples contained no message for either isoform. Substrate turnover by udpgth-3 is ranked as follows: phenolphthalein > 5 alpha-androstane-3 alpha,17 beta-diol > 5 alpha- dihydrotestosterone = 4-hydroxybiphenyl > phenolsulfonphthalein (phenol red) > phenolphthalin. Genes encoding udpgth-3, udpgth-2, and udpgth-1 mapped to human chromosome 4 with genomic DNA from human/mouse and human/hamster somatic cell hybrids; the genes encoding udpgth-1 and udpgth-2 mapped specifically to band 4q28. udpgth-3 exhibited similar Km values both for 5 alpha-dihydrotestosterone (10 microM) and for its metabolite, 5 alpha-androstane-3 alpha,-17 beta-diol (12.5 microM).(ABSTRACT TRUNCATED AT 400 WORDS)

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Northern
  • Chromosome Mapping
  • Chromosomes, Human, Pair 4*
  • Cloning, Molecular
  • DNA, Complementary / metabolism
  • Erythrocebus patas
  • Glucuronosyltransferase / biosynthesis*
  • Glucuronosyltransferase / genetics
  • Glucuronosyltransferase / metabolism
  • Humans
  • Isoenzymes / biosynthesis*
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Kinetics
  • Liver / enzymology*
  • Male
  • Molecular Sequence Data
  • Organ Specificity
  • Prostate / enzymology
  • RNA, Messenger / analysis
  • RNA, Messenger / biosynthesis
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Testis / enzymology


  • DNA, Complementary
  • Isoenzymes
  • RNA, Messenger
  • Recombinant Proteins
  • Glucuronosyltransferase