Inhibitors of orotate phosphoribosyl-transferase and orotidine-5'-phosphate decarboxylase from mouse Ehrlich ascites cells: a procedure for analyzing the inhibition of a multi-enzyme complex.

@article{Traut1977InhibitorsOO,
  title={Inhibitors of orotate phosphoribosyl-transferase and orotidine-5'-phosphate decarboxylase from mouse Ehrlich ascites cells: a procedure for analyzing the inhibition of a multi-enzyme complex.},
  author={T. Traut and M. E. Jones},
  journal={Biochemical pharmacology},
  year={1977},
  volume={26 23},
  pages={
          2291-6
        }
}
Abstract Orotate phosphoribosyltransferase and orotidine-5'-phosphate decarboxylase, the last two enzymes in the pathway for de novo pyrimidine biosynthesis, exist as a multi-enzyme complex in mammalian cells. Because the two enzymes are not separable, assays for the phosphoribosyltransferase are normally dependent on the decarboxylase, and this has in the past produced misinterpretations in evaluating the effects of inhibitors of either enzyme activity. We have developed a procedure for… Expand
Significance of the enzyme complex that synthesizes UMP in Ehrlich ascites cells.
  • T. Traut
  • Biology, Medicine
  • Archives of biochemistry and biophysics
  • 1980
TLDR
The results suggest that the capability for channeling OMP may have been important in evolving the enzyme complex found in mammalian cells. Expand
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This chapter describes purification procedure related to the orotate phosphoribosyltransferase enzyme, useful when one wishes to estimate how effective inhibitors of the decarboxylase are when the OMP level is that maintained at a steady-state level by the complex itself. Expand
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In studies utilizing cell-free lysates of WI-L2, chemically prepared APR-TC-5'P provided potent inhibition of the orotidylate decarboxylase activity of the UMP synthase complex, and a Ki value of 0.35 nM was determined. Expand
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It is suggested that phosphoribosyltransferase in S. mansoni plays a role in both de novo UMP biosynthesis as well as in the salvage of uracil and uridine. Expand
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It is suggested that the 4.8 S conformer might be expected to exist in the cytosol, in vivo, and whether Complex U is a multifunctional protein so that the two enzymatically active centers reside on a singly polypeptide chain. Expand
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TLDR
The appropriate computer simulation demonstrates that low transient levels of OMP and protection of the intermediate are provided for strictly by the kinetic parameters of orotate phosphoribosyltransferase, OMP decarboxylase, and the nucleotidase. Expand
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TLDR
Evidence for a regulatory site, distinct from either of the two catalytic sites, which appears to mediate the conversion of the 5.6S form upon binding certain pyrimidine nucleotides (OMP, UMP, and 6-azaUMP) is presented. Expand
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TLDR
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TLDR
A structure-activity relationship has been formulated for the binding of pyrimidine base analogs to OPRTase, and several such compounds are proposed. Expand
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Purification, size, and properties of the complex of orotate phosphoribosyltransferase: orotidylate decarboxylase from mouse Ehrlich ascites carcinoma.
TLDR
The stability studies have led to the development of conditions that permit one, for the first time, to subject the complex to electrophoresis and to recover a large percentage of both enzyme activities, rather than only decarboxylase activity as has occurred in the past. Expand
Radioassay of orotic acid phosphoribosyltransferase and orotidylate decarboxylase utilizing a high-voltage paper electrophoresis technique or an improved 14CO2- release method.
TLDR
For purification of the enzyme complex, the release of 14 CO 2 from [ 14 C]carboxyl-labeled orotic acid is preferable to the HVPE method as a routine assay procedure and the most economical CO 2 -absorbant for the assay of the enzymes complex or for orotidylate decarboxylase is an NaOH-soaked paper strip. Expand
Studies on a pyrimidine phosphoribosyltransferase from murine leukemia P1534J. Partial purification, substrate specificity, and evidence for its existence as a bifunctional complex with orotidine 5-phosphate decarboxylase.
TLDR
The apparent Km and Ki values reported in this study indicate that the preferred pyrimidine substrate is orotate, and it seems likely, therefore, that this enzyme functions in vivo as an orotated phosphoribosyltransferase. Expand
Alteration of quaternary structural behaviour of an hepatic orotate phosphoribosyltransferase-orotidine-5'-phosphate decarboxylase complex in rats following allopurinol therapy.
TLDR
Evidence is presented that both enzymic activities reside in a single protein moiety capable of association-dissociation phenomena, and allopurinol administration resulted in the formation of an inhibitor (or inhibitors) of these enzymes. Expand
Kinetic properties and inhibition of orotidine 5'-phosphate decarboxylase. Effects of some allopurinol metabolites on the enzyme.
TLDR
The findings furnish direct, quantitative support for the idea that it is the inhibition of orotidine 5'-phosphate decarboxylase by the nucleotides of oxipurinol that is primarily responsible for the increased urinary excretion of Orotic acid and orotazine in patients treated with allopurinols. Expand
Effect of allopurinol and its metabolic derivatives on the configuration of human orotate phosphoribosyltransferase and orotidine 5'-phosphate decarboxylase.
TLDR
It is shown that human orotate phosphoribosyltransferase and orotidine 5'-phosphate decarboxylase exist in a complex as three different molecular species with molecular weights of 55,000, 80,000 and 113,000; the larger forms of the complex are more stable than the small form. Expand
Activity and distribution of the enzymes of uridylate synthesis from orotate in animal tissues.
TLDR
Under a variety of conditions, including fast growing tissues, OMP pyrophosphorylase and OMP decarboxylase showed closely parallel, possibly coordinate changes in activity. Expand
Mechanism of allopurinol-mediated inhibition and stabilization of human orotate phosphoribosyltransferase and orotidine phosphate decarboxylase.
TLDR
Findings suggest that the apparent increase of OPRT and ODC activity after allopurinol therapy is due to stabilization of the enzymes during the life span of the erythrocytes. Expand
Purification and kinetic properties of brain orotidine 5'-phosphate decarboxylase.
  • S. Appel
  • Medicine, Chemistry
  • The Journal of biological chemistry
  • 1968
TLDR
During purification and heat denaturation experiments, activity of orotidine 5'-phosphate pyrophosphorylase appears to parallel orotIDS decarboxylase activity, and it appears unlikely that the observed inhibition serves a role in regulating pyrimidine levels. Expand
Effect of allopurinol and oxipurinol on pyrimidine synthesis in cultured human fibroblasts.
TLDR
Observations provide several possible mechanisms to account for the modest inhibitory effect of allopurinol on pyrimidine biosynthesis, but fail to accounts for the even more striking inhibition produced by oxipur inol in cell culture. Expand
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