Phenol UDP-glucuronosyltransferase Research Articles

Activities of pollutant metabolising and detoxication systems in the liver of the plaice, Pleuronectes platessa: Sex and seasonal variations in non-induced fish

1. The ability of immature plaice to perform a number of representative hepatic phase I and II biotransformations was examined. 2. Activities attributable to cytochrome P-450 1A1 and phenol UDP-glucuronosyltransferase activity were markedly higher in plaice than other fish or rats. Glucuronidation of sex hormones and bilirubin, conjugation of ethacrynic acid with glutathione and the sulphation of phenols was very much lower in plaice than in rats, indicating that these are minor pathways in this fish. 3. MFO activities in sexually mature female plaice were 20–25% of those in immature fish, whilst there were no significant differences in glutathione S-transferase or glutathione peroxidase activity. 4. Seasonal variations in activities were determined for use in biomonitoring studies. With the exception of microsomal GST, all enzymes and the liver somatic index showed a marked seasonal variation, activities were lower in summer and showed a gradual rise in autumn and winter with a peak in spring. This pattern appeared to be the inverse of the environmental temperature, indicative of a possible temperature-dependent effect; however, there was not direct proportionality and photoperiod, feeding behaviour, plasma corticosteroid and plasma glucose also show a similar cyclical variation. 5. Cytochrome P-450 dependent ethoxyresorufin O-deethylase and cytosolic glutathione S-transferase activities in immature male fish showed a two-fold elevation over those in immature females during late winter and spring in the period when gonadal regression might be occurring and may be due to elevated 11-ketotestosterone levels.

Chromosomal mapping of a human phenol UDP‐glucuronosyltransferase, GNT1

A 5' fragment of a full-length cDNA clone encoding a human phenol UDP-glucuronosyltransferase was used to produce a specific probe for this gene. DNA isolated from a panel of 18 human-rodent somatic cell hybrids was analysed by Southern-blot hybridization. The results indicate that this UDP-glucuronosyltransferase is encoded by a single gene, designated GNT1, located on human chromosome 2.

Phenol UDP-glucuronosyltransferase deficiency in Gunn rats: mRNA levels are considerably reduced

Phenol UDP-glucuronosyltransferase deficiency in Gunn rats: mRNA levels are considerably reduced

Cloning and substrate specificity of a human phenol UDP-glucuronosyltransferase expressed in COS-7 cells.

A rat kidney phenol UDP-glucuronosyltransferase cDNA was used to isolate a human liver phenol UDP-glucuronosyltransferase cDNA by screening of a human liver cDNA library in the expression vector lambda gt11. The 2.4-kilobase cDNA contained an open reading frame of 1593 base pairs coding for a protein of 531 residues. The human liver cDNA was subcloned into the vector pKCRH2. Transfection of this recombinant plasmid into COS-7 cells allowed the expression of a protein of approximately 55 kDa. The enzyme synthesized was a glycoprotein, as indicated by a reduction in molecular mass of approximately 3 kDa after biosynthesis in the presence of tunicamycin. The expressed enzyme rapidly catalyzed the glucuronidation of 1-naphthol, 4-methylumbelliferone, and 4-nitrophenol. The use of a related series of simple phenols provided an outline description of the substituent restrictions imposed upon the phenolic structures accepted as substrates. The glucuronidation of testosterone, androsterone, and estrone was not catalyzed by this cloned UDP-glucuronosyltransferase.

Properties of a 3-methylcholanthrene-inducible phenol UDP-glucuronosyltransferase from rat liver

Functional and molecular probes are described which are useful to identify a 3-methylcholanthrene-inducible phenol UDP-glucuronosyltransferase (GT MC) from rat liver. Two different procedures for isolation of GT MC were compared, method 1 utilizing DEAE-Sepharose chromatography or method 2, chromatofocusing. Method 2 appeared to be superior in separating different isoenzymes. Subsequently the enzyme was purified by affinity chromatography on UDP-hexanolamine Sepharose. With both methods a protein was purified with a subunit M r of 55,000, catalyzing glucuronidation of a variety of planar phenols and, in particular, of benzo(a)pyrene-3,6-quinol to its mono- and diglucuronide. Antibodies to GT MC recognized a polypeptide with a subunit M r of 55,000 as the major 3-methylcholanthrene-inducible isoenzyme in rat liver microsomes. The described functional and molecular probes may help to differentiate GT MC from similar isoenzymes conjugating planar phenols and to elucidate its regulation and biological function.

A simple radiometric procedure for measuring phenol UDP-glucuronosyltransferase activity in vitro and some properties of the enzyme [proceedings

A simple radiometric procedure for measuring phenol UDP-glucuronosyltransferase activity in vitro and some properties of the enzyme [proceedings