Pyrophosphatase and glucuronosyltransferase in microsomal UDPglucuronic-acid metabolism in the rat liver.

@article{Puhakainen1976PyrophosphataseAG,
  title={Pyrophosphatase and glucuronosyltransferase in microsomal UDPglucuronic-acid metabolism in the rat liver.},
  author={Eino Puhakainen and Osmo O P H{\"a}nninen},
  journal={European journal of biochemistry},
  year={1976},
  volume={61 1},
  pages={
          165-9
        }
}
1. A radiochemical method for the studies on the microsomal UDPglucuronic acid metabolism has been developed. 2. The rat liver microsomes caused a rapid hydrolysis of UDPglucuronic acid to D-glucuronic acid 1-phosphate and further although much slower to free D-glucuronic acid. In Tris-HCl buffer (pH 7.4) they were produced in ratio 72 : 1. No other metabolites were found in measurable amounts. The pyrophosphatase splitting UDPglucuronic acid showed a pH optimum at 8.9, but the liberation of D… 
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HepaticMicrosomalN-Glucuronidationand NucleicAcid Binding of N-HydroxyArylaminesin Relationto Urinary Bladder Carcinogenesis1
TLDR
The hydrolysis of the glucuronides to Nhydroxy arylamines and the conversion of the latter deniva tives to highly reactive electrophilic amylnitrenium ions in the normally acidic urine of dogs and humans may be critical reactions for tumor induction in the urinary bladder.
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References

SHOWING 1-10 OF 20 REFERENCES
Nucleotide Pyrophosphatase of Rat Liver
Studies on the subcellular distribution of ratliver nucleotide pyrophosphatase activity revealed its presence in the plasma membrane and the endoplasmic reticulum only. The enzymes from either source
Nucleotide activation of liver microsomal glucuronidation.
Assay of UDPG1cUA pyrophosphatase and its relation to transglucuronidation.
  • K. Wong, Y. Lau
  • Biology, Chemistry
    Biochimica et biophysica acta
  • 1970
Nucleotide pyrophosphatase activity of rat liver plasma membranes.
...
1
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