User menu

Accès à distance ? S'identifier sur le proxy UCLouvain

Glucuronate, the precursor of vitamin C, is directly formed from UDP-glucuronate in liver.

Primary tabs

Linster, Carole [UCL] Van Schaftingen, Emile [UCL]

The conversion of UDP-glucuronate to glucuronate, usually thought to proceed by way of glucuronate 1-phosphate, is a site for short-term regulation of vitamin C synthesis by metyrapone and other xenobiotics in isolated rat hepatocytes. Our purpose was to explore the mechanism of this effect in cell-free systems. Metyrapone and other xenobiotics stimulated, by approximately threefold, the formation of glucuronate from UDP-glucuronate in liver extracts enriched with ATP-Mg, but did not affect the formation of glucuronate 1-phosphate from UDP-glucuronate or the conversion of glucuronate 1-phosphate to glucuronate. This and other data indicated that glucuronate 1-phosphate is not an intermediate in glucuronate formation from UDP-glucuronate, suggesting that this reaction is catalysed by a 'UDP-glucuronidase'. UDP-glucuronidase was present mainly in the microsomal fraction, where its activity was stimulated by UDP-N-acetylglucosamine, known to stimulate UDP-glucuronosyltransferases by enhancing the transport of UDP-glucuronate across the endoplasmic reticulum membrane. UDP-glucuronidase and UDP-glucuronosyltransferases displayed similar sensitivities to various detergents, which stimulated at low concentrations and generally inhibited at higher concentrations. Substrates of glucuronidation inhibited UDP-glucuronidase activity, suggesting that the latter is contributed by UDP-glucuronosyltransferase(s). Inhibitors of beta-glucuronidase and esterases did not affect the formation of glucuronate, arguing against the involvement of a glucuronidation-deglucuronidation cycle. The sensitivity of UDP-glucuronidase to metyrapone and other stimulatory xenobiotics was lost in washed microsomes, even in the presence of ATP-Mg, but it could be restored by adding a heated liver high-speed supernatant or CoASH. In conclusion, glucuronate formation in liver is catalysed by a UDP-glucuronidase which is closely related to UDP-glucuronosyltransferases. Metyrapone and other xenobiotics stimulate UDP-glucuronidase by antagonizing the inhibition exerted, presumably indirectly, by a combination of ATP-Mg and CoASH.

  1. Smirnoff N, Vitam Horm, 61, 241 (2001)
  2. Hiatt HH, The Metabolic and Molecular Bases of Inherited Disease, 1589 (2001)
  3. Wang YM, N Engl J Med, 282, 892 (1970)
  4. Linster CL, J Biol Chem, 278, 36328 (2003)
  5. Ginsburg V, Biochim Biophys Acta, 28, 649 (1958)
  6. PUHAKAINEN Eino, HANNINEN Osmo, Pyrophosphatase and Glucuronosyltransferase in Microsomal UDPglucuronic-Acid Metabolism in the Rat Liver, 10.1111/j.1432-1033.1976.tb10007.x
  7. Pogell BM, J Biol Chem, 236, 293 (1961)
  8. Horio F, J Nutr, 123, 2075 (1993)
  9. Bhatnagar A, Biochem Pharmacol, 39, 1115 (1990)
  10. Fulceri R., Banhegyi G., Gamberucci A., Giunti R., Mandl J., Benedetti A., Evidence for the Intraluminal Positioning of p-Nitrophenol UDP-glucuronosyltransferase Activity in Rat Liver Microsomal Vesicles, 10.1006/abbi.1994.1081
  11. Bossuyt X, Blanckaert N, Mechanism of stimulation of microsomal UDP-glucuronosyltransferase by UDP-N-acetylglucosamine, 10.1042/bj3050321
  12. Zakim David, Vessey Donald A., Regulation of microsomal enzymes by phospholipids, 10.1016/0005-2744(75)90207-7
  13. Lett E, Biochem Pharmacol, 43, 1649 (1992)
  14. Shepherd S R, Baird S J, Hallinan T, Burchell B, An investigation of the transverse topology of bilirubin UDP-glucuronosyltransferase in rat hepatic endoplasmic reticulum, 10.1042/bj2590617
  15. Jansen PLM, Hepatology, 15, 532 (1992)
  16. Pan Chi-Jiann, Lei Ke-Jian, Annabi Borhane, Hemrika Wieger, Chou Janice Yang, Transmembrane Topology of Glucose-6-Phosphatase, 10.1074/jbc.273.11.6144
  17. Levvy G. A., The preparation and properties of β-glucuronidase. 4. Inhibition by sugar acids and their lactones, 10.1042/bj0520464
  18. HEYMANN Eberhard, MENTLEIN Rolf, SCHMALZ Rainer, SCHWABE Christian, WAGENMANN Frank, A Method for the Estimation of Esterase Synthesis and Degradation and its Application to Evaluate the Influence of Insulin and Glucagon, 10.1111/j.1432-1033.1979.tb04267.x
  19. Touster O., ISOLATION OF RAT LIVER PLASMA MEMBRANES: Use of Nucleotide Pyrophosphatase and Phosphodiesterase I as Marker Enzymes, 10.1083/jcb.47.3.604
  20. Evans W. Howard, Hood Diana O., Gurd James W., Purification and properties of a mouse liver plasma-membrane glycoprotein hydrolysing nucleotide pyrophosphate and phosphodiester bonds, 10.1042/bj1350819
  21. Evans WH, Nature, 250, 391 (1974)
  22. Bachorik PS, J Biol Chem, 247, 5071 (1972)
  23. BISCHOFF Erwin, TRAN-THI Thuy-Anh, DECKER Karl F. A., Nucleotide Pyrophosphatase of Rat Liver. A Comparative Study on the Enzymes Solubilized and Purified from Plasma Membrane and Endoplasmic Reticulum, 10.1111/j.1432-1033.1975.tb03935.x
  24. de Duve C., Pressman B. C., Gianetto R., Wattiaux R., Appelmans F., Tissue fractionation studies. 6. Intracellular distribution patterns of enzymes in rat-liver tissue, 10.1042/bj0600604
  25. HIMENO Masaru, NISHIMURA Yukio, TSUJI Hiroshi, KATO Keitaro, Purification and Characterization of Microsomal and Lysosomal beta-Glucuronidase from Rat Liver by Use of Immunoaffinity Chromatography, 10.1111/j.1432-1033.1976.tb11024.x
  26. Owens J.William, Stahl Philip, Purification and characterization of rat liver microsomal β-glucuronidase, 10.1016/0005-2744(76)90263-1
  27. Amar-Costesec A., ANALYTICAL STUDY OF MICROSOMES AND ISOLATED SUBCELLULAR MEMBRANES FROM RAT LIVER: II. Preparation and Composition of the Microsomal Fraction, 10.1083/jcb.61.1.201
  28. RADOMINSKA-PANDYA ANNA, CZERNIK PIOTR J., LITTLE JOANNA M., BATTAGLIA ERIC, MACKENZIE PETER I., STRUCTURAL AND FUNCTIONAL STUDIES OF UDP-GLUCURONOSYLTRANSFERASES*, 10.1081/dmr-100101944
  29. Frick David N., Townsend Benjamin D., Bessman Maurice J., A Novel GDP-Mannose Mannosyl Hydrolase Shares Homology with the MutT Family of Enzymes, 10.1074/jbc.270.41.24086
  30. Zakim David, Goldenberg Jovita, Vessey Donald A., Influence of Membrane Lipids on the Regulatory Properties of UDP-Glucuronyltransferase, 10.1111/j.1432-1033.1973.tb03033.x
  31. Burchell Brian, Brierley Catherine H, Rance David, Specificity of human UDP-Glucuronosyltransferases and xenobiotic glucuronidation, 10.1016/0024-3205(95)02073-r
  32. Ethell BT, Biochem Pharmacol, 65, 1441 (2003)
  33. Iyanagi T, J Biol Chem, 264, 21302 (1989)
  34. Iyanagi T, J Biol Chem, 266, 24048 (1991)
  35. Hochman Y, J Biol Chem, 259, 5521 (1984)
  36. Yamashita A, Biochem Pharmacol, 53, 561 (1997)
  37. Lowry OH, J Biol Chem, 193, 265 (1951)
  38. Linster CL, Protein Expr Purif, 37, 352 (2004)
Bibliographic reference Linster, Carole ; Van Schaftingen, Emile. Glucuronate, the precursor of vitamin C, is directly formed from UDP-glucuronate in liver.. In: FEBS Journal, Vol. 273, no. 7, p. 1516-1527 (2006)
Permanent URL http://hdl.handle.net/2078.1/10586