SOME DIFFERENCES IN THE CONJUGATION OF O-AMINOPHENOL AND P-NITROPHENOL BY THE URIDINE DIPHOSPHATE TRANSGLUCURONYLASE OF MOUSE-LIVER HOMOGENATES.
1. Glucuronide synthesis from uridine diphosphate glucuronate and o-aminophenol or p-nitrophenol in the presence of uridine diphosphate transglucuronylase of mouse-liver homogenates has been studied with respect to inhibition by compounds known to be conjugated under the experimental conditions, and also by thiophenol. 2. Raising the o-aminophenol concentration decreased the inhibition of o-aminophenyl glucuronide synthesis by the alternative glucuronyl acceptors phenol, menthol and benzoic acid, but was without effect on that caused by p-nitrophenol and thiophenol. 3. Raising the p-nitrophenol concentration decreased or abolished the inhibition of p-nitrophenyl glucuronide synthesis due to phenol, menthol, benzoic acid, anthranilic acid, o-aminophenol and thiophenol. 4. The o-aminophenol system was much more readily inhibited by all compounds than the p-nitrophenol system. 5. In tris buffer, pH7.4, over 30% activation of the o-aminophenol system was achieved by 2mm-Mg(2+), but 10mm-Mg(2+) was inhibitory. The p-nitrophenol system showed only inhibition from 2mm-Mg(2+) upwards. 6. The results are discussed as suggesting that there are at least two uridine diphosphate transglucuronylases.
D000627:Aminophenols; D000818:Animals; D001565:Benzoates; D004791:Enzyme Inhibitors; D005964:Glucosyltransferases; D008099:Liver / Q000201:enzymology* / Q000502:physiology*; D008274:Magnesium; D008610:Menthol; D051379:Mice; D009596:Nitrophenols; D010600:Pharmacology; D010636:Phenols; D012106:Research; D013438:Sulfhydryl Compounds; D014500:Uracil Nucleotides; D014529:Uridine; D014530:Uridine Diphosphate; D062367:ortho-Aminobenzoates
D000627:Aminophenols; D001565:Benzoates; D004791:Enzyme Inhibitors; D009596:Nitrophenols; D010636:Phenols; D013438:Sulfhydryl Compounds; D014500:Uracil Nucleotides; D062367:ortho-Aminobenzoates; C031385:anthranilic acid; D008610:Menthol; C027667:2-aminophenol; D014530:Uridine Diphosphate; C042983:thiophenol; D005964:Glucosyltransferases; D008274:Magnesium; D014529:Uridine; C024836:4-nitrophenol
ANTHRANILIC ACID; BENZOATES; ENZYME INHIBITORS; EXPERIMENTAL LAB STUDY; GLUCOSYLTRANSFERASES; HOMOGENATES; LIVER ENZYMOLOGY; LIVER FUNCTION; MAGNESIUM; MENTHOL; MICE; NITROPHENOLS; PHARMACOLOGY; PHENOLS; SULFHYDRYL COMPOUNDS; URACIL NUCLEOTIDES