Metabolic regulation of ATP breakdown and of adenosine production in rat brain extracts

Barsotti, Catia; Ipata, Piero Luigi

doi:10.1016/j.biocel.2004.04.015

Cited by 71 publications

(74 citation statements)

References 52 publications

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“…Moreover, as observed for other purine nucleosides (31), its level might well increase in anoxic conditions since Xao accumulates in rat brain extract during GTP (13) and GMP (32) breakdown due to the presence of the so-called "ribose 1-phosphate recycling for nucleoside interconversion" (12). It is noteworthy that IMP, the preferred phosphate donor to Xao, accumulates during ATP breakdown in anoxic-like conditions (4,13). It might be speculated that, as it occurs for the other purine and pyrimidine nucleosides, the process of Xao salvage is particularly active during the reperfusion period.…”

Section: Nadmentioning

confidence: 78%

“…Its level specifically increases in patients with chronic renal failure (30). Moreover, as observed for other purine nucleosides (31), its level might well increase in anoxic conditions since Xao accumulates in rat brain extract during GTP (13) and GMP (32) breakdown due to the presence of the so-called "ribose 1-phosphate recycling for nucleoside interconversion" (12). It is noteworthy that IMP, the preferred phosphate donor to Xao, accumulates during ATP breakdown in anoxic-like conditions (4,13).…”

Section: Nadmentioning

confidence: 86%

“…tions mimicking anoxia (13). Protein concentration was determined by the Coomassie Blue binding assay using bovine serum albumin as standard (14).…”

Section: Methodsmentioning

confidence: 99%

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Evidence for the Involvement of Cytosolic 5′-Nucleotidase (cN-II) in the Synthesis of Guanine Nucleotides from Xanthosine

Barsotti

Pesi

Giannecchini

et al. 2005

Journal of Biological Chemistry

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In this paper, we show that in vitro xanthosine does not enter any of the pathways known to salvage the other three main natural purine nucleosides: guanosine; inosine; and adenosine. In rat brain extracts and in intact LoVo cells, xanthosine is salvaged to XMP via the phosphotransferase activity of cytosolic 5-nucleotidase. IMP is the preferred phosphate donor (IMP ؉ xanthosine 3 XMP ؉ inosine). XMP is not further phosphorylated. However, in the presence of glutamine, it is readily converted to guanyl compounds. Thus, phosphorylation of xanthosine by cytosolic 5-nucleotidase circumvents the activity of IMP dehydrogenase, a rate-limiting enzyme, catalyzing the NAD ؉ -dependent conversion of IMP to XMP at the branch point of de novo nucleotide synthesis, thus leading to the generation of guanine nucleotides. Mycophenolic acid, an inhibitor of IMP dehydrogenase, inhibits the guanyl compound synthesis via the IMP dehydrogenase pathway but has no effect on the cytosolic 5-nucleotidase pathway of guanine nucleotides synthesis. We propose that the latter pathway might contribute to the reversal of the in vitro antiproliferative effect exerted by IMP dehydrogenase inhibitors routinely seen with repletion of the guanine nucleotide pools.

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Section: Nadmentioning

confidence: 78%

Section: Nadmentioning

confidence: 86%

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Evidence for the Involvement of Cytosolic 5′-Nucleotidase (cN-II) in the Synthesis of Guanine Nucleotides from Xanthosine

Barsotti

Pesi

Giannecchini

et al. 2005

Journal of Biological Chemistry

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“…ATP is progressively degraded to nucleotides and nucleosides under ischemia or hypoxia. 17,18 The major metabolic event during the ischemic period is salvage of the nucleotides such as IMP. 19 However, the role of the purine nucleotide pathway and the metabolites that participate in the regulation of reperfusion injuries remain unknown.…”

Section: Discussionmentioning

confidence: 99%

Remote Reperfusion Lung Injury is Associated With AMP Deaminase 3 Activation and Attenuated by Inosine Monophosphate

Oginö

Hoshikawa

et al. 2007

Circ J

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“…Adenosine is a metabolite, an important neuroactive nucleoside, and a homeostatic cellular modulator [5,6]. Extracellular adenosine is an important stress hormone that is released in excessive amounts in the vicinity of immune cells during both systemic and cellular stress.…”

Section: Purine Catabolismmentioning

confidence: 99%

From purines to basic biochemical concepts

Marini¹,

Ipata²

2007

Biochem Molecular Bio Educ

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Many high school biology courses address mainly the molecular and cellular basis of life. The complexity that underlies the most essential processes is often difficult for the students to understand; possibly, in part, because of the inability to see and explore them. Six simple practical experiments on purine catabolism as a part of a biochemistry course for 16-18 years students that require only simple equipment for thin layer chromatography have been developed, tried, and tested. These include detection and measurement of enzyme activities in biological extracts, detection of reversible and irreversible reactions, creating a pathway from consecutive reactions. They focus on purines because of their multifunctionality in biochemical processes. They allow students to grasp specific concepts and to use them as a framework for approaching metabolic complexity.

show abstract

Metabolic regulation of ATP breakdown and of adenosine production in rat brain extracts

Cited by 71 publications

References 52 publications

Evidence for the Involvement of Cytosolic 5′-Nucleotidase (cN-II) in the Synthesis of Guanine Nucleotides from Xanthosine

Evidence for the Involvement of Cytosolic 5′-Nucleotidase (cN-II) in the Synthesis of Guanine Nucleotides from Xanthosine

Remote Reperfusion Lung Injury is Associated With AMP Deaminase 3 Activation and Attenuated by Inosine Monophosphate

From purines to basic biochemical concepts

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