Relationships among purine nucleoside metabolism, adenosine triphosphate catabolism, and glycolysis in human erythrocytes

Jf, Henderson; Zombor, George; Pw, Burridge; Barankiewicz, G; Cm, Smith

doi:10.1139/o79-107

Cited by 16 publications

(9 citation statements)

References 4 publications

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“…In mature erythrocytes, even more than in other cell types, adenine nucleotides constitute the most abundant nucleotide compounds. 5'-Nucleotidase(s) intervene(s) in their catabolism by dephosphorylating either AMP or its deamination product IMP, depending on the experimental conditions [6][7][8][9]. Yet the precise identity of the enzyme(s) responsible for this process has not been determined with certainty.…”

Section: Introductionmentioning

confidence: 99%

5′-Nucleotidase activities in human erythrocytes. Identification of a purine 5′-nucleotidase stimulated by ATP and glycerate 2,3-bisphosphate

Bontemps

Berghe

Hers

1988

Biochemical Journal

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A purine 5'-nucleotidase has been separated by DEAE-Trisacryl chromatography from other 5'-nucleotidase activities present in human haemolysates and purified approx. 30,000-fold by subsequent chromatography on Blue Sepharose. The enzyme has an Mr of around 250,000, displays hyperbolic substrate-saturation kinetics and hydrolyses preferentially IMP, GMP and their deoxy counterparts. It is much less active with AMP and dAMP. The purine 5'-nucleotidase is inhibited by Pi, and is strongly stimulated by ATP, dATP and GTP, and by glycerate 2,3-bisphosphate. Stimulators decrease Km and increase Vmax. Glycerate 2,3-bisphosphate is the most potent stimulator of the enzyme and, under physiological conditions, over-rides the influence of the other effectors. Glycerate 2,3-bisphosphate also influences the binding of the enzyme to DEAE-Trisacryl, as evidenced by the different elution profile obtained with fresh as compared with outdated blood. It is concluded that the glycerate 2,3-bisphosphate-stimulated purine 5'-nucleotidase is responsible for the dephosphorylation of IMP and GMP, but not of AMP, in human erythrocytes.

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Section: Introductionmentioning

confidence: 99%

5′-Nucleotidase activities in human erythrocytes. Identification of a purine 5′-nucleotidase stimulated by ATP and glycerate 2,3-bisphosphate

Bontemps

Berghe

Hers

1988

Biochemical Journal

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“…The inhibition of both enzymes should produce accumulation of adenosine. A few studies have assessed the involvement of deamination and dephosphorylation of AMP in the breakdown of erythrocytic ATP induced by various drugs and metabolic inhibitors (9,10). The catabolism of the adenine nucleotides under physiologic conditions and its acceleration provoked by lack of glucose (1 1), alkalinization of the medium (12,13), and depletion of Pi (14)(15)(16) have, however, not been investigated in this respect, nor has the possibility of a recycling of adenosine been evaluated.…”

Section: Introductionmentioning

confidence: 99%

Pathways of adenine nucleotide catabolism in erythrocytes.

1986

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The exact pathway whereby the initial catabolism of the adenine nucleotides proceeds from AMP and the possibility of a recycling of adenosine were investigated in human erythrocytes. Adenine nucleotide catabolism, reflected by the production of hypoxanthine, is very slow under physiologic conditions and can be greatly increased by suppression of glucose or alkalinization of the medium. Experiments with inhibitors of adenosine deaminase and adenosine kinase demonstrated that under physiologic conditions the initial catabolism of AMP proceeds by way of a deamination of AMP, followed by dephosphorylation of inosine monophosphate, and that no recycling occurs between AMP and adenosine. Under glucose deprivation, -75% of the 20-fold increase of the catabolism of the adenine nucleotides proceeded by way of a dephosphorylation of AMP followed by deamination of adenosine, and a small recycling of this nucleoside could be evidenced. Inhibition of adenosine transport showed that the dephosphorylation of AMP occurred intracellularly. When the incubation medium was alkalinized in the presence of glucose, the 15-fold increase in the conversion of AMP to hypoxanthine proceeded exclusively by way of AMP deaminase but a small recycling of adenosine could also be evidenced. The threefold elevation of intraerythrocytic inorganic phosphate (PI) during glucose deprivation and its 50% decrease during alkalinization as well as experiments in which extracellular P1 was modified, indicate that the dephosphorylation of red blood cell AMP is mainly responsive to variations of AMP, whereas its deamination is more sensitive to Pi.

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“…Both NH( and Pi may exert their effect on ATP and DPG metabolism by several mechanisms. It is known that NH4 has a stimulatory action on the pentose phosphate pathway [20][21][22][23], This may result in the increased formation of phosphoribosylpyrophosphate (PRPP) which is needed for the phosphorylation of ade nine by adenine phsophoribosyltransferase [24]. Kay and Beutler [4] found that the activity of APRT was unaffected by ammonium ions.…”

Section: Discussionmentioning

confidence: 99%

Studies in Red Blood Cell Preservation

Greenwalt¹,

Dumaswala²,

Dhingra³

et al. 1993

Vox Sanguinis

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Studies were conducted to examine whether an experimental additive solution (EAS-2) containing, in mM: 20 NH(4)Cl, 30 Na(2)HPO)4), 2 adenine, 110 dextrose, 55 mannitol, pH 7.15, would be useful to extend the storage shelf life of human RBCs. With 6 pairs of split units, ATP concentrations were better maintained for 12 weeks with EAS-2 than with Adsol® (1.8 vs. 1.1 µmol/gHb, respectively, p = 0.002). Autologous 24-hours 51Cr viability values for split units in the same donors were: on 6 paired units at 8 weeks, EAS-2 87.0±4.5%, Adsol 72.6±2.3%, p = 0.004; on 11 paired units at 9 weeks, EAS-2 79.5±7.1%, Adsol 68.2±10.1%, p = 0.0003. The data suggest that packed RBCs stored for 9 weeks with EAS-2 will be suitable for transfusion following the removal of supernatant with a single washing step.

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Relationships among purine nucleoside metabolism, adenosine triphosphate catabolism, and glycolysis in human erythrocytes

Cited by 16 publications

References 4 publications

5′-Nucleotidase activities in human erythrocytes. Identification of a purine 5′-nucleotidase stimulated by ATP and glycerate 2,3-bisphosphate

5′-Nucleotidase activities in human erythrocytes. Identification of a purine 5′-nucleotidase stimulated by ATP and glycerate 2,3-bisphosphate

Pathways of adenine nucleotide catabolism in erythrocytes.

Studies in Red Blood Cell Preservation

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