Oxypurine cycle in human erythrocytes regulated by pH, inorganic phosphate, and oxygen.

Berman, Peter; Black, D. A.; Human, L.; Harley, Eric H.

doi:10.1172/jci113707

Cited by 34 publications

(33 citation statements)

References 29 publications

(17 reference statements)

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“…The data for the basal evaluation suggested that the energetic homeostasis was maintained in the RBCs under the present method. The present alkaline information agreed with the changes in the RBCs in alkaline media except the IMP, uric acid and AEC values (Minakami and Yoshikawa 1966;Tsuda et al 1975;Bontemps et al 1986;Berman et al 1988). The IMP value in alkaline samples differed from previous reports because the alkaline evaluations did not observed changes or showed a reduction of IMP.…”

Section: Discussionsupporting

confidence: 85%

A Novel Method for Measuring the ATP-Related Compounds in Human Erythrocytes

Aragón-Martínez

Galicia-Castillo

Isiordia-Espinoza

et al. 2014

Tohoku J. Exp. Med.

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The ATP-related compounds in whole blood or red blood cells have been used to evaluate the energy status of erythrocytes and the degradation level of the phosphorylated compounds under various conditions, such as chronic renal failure, drug monitoring, cancer, exposure to environmental toxics, and organ preservation. The complete interpretation of the energetic homeostasis of erythrocytes is only performed using the compounds involved in the degradation pathway for adenine nucleotides alongside the uric acid value. For the first time, we report a liquid chromatographic method using a diode array detector that measures all of these compounds in a small human whole blood sample (125 μL) within an acceptable time of 20 min. The stability was evaluated for all of the compounds and ranged from 96.3 to 105.1% versus the day zero values. The measurement had an adequate sensitivity for the ATP-related compounds (detection limits from 0.001 to 0.097 μmol/L and quantification limits from 0.004 to 0.294 μmol/L). This method is particularly useful for measuring inosine monophosphate, inosine, hypoxanthine, and uric acid. Moreover, this assay had acceptable linearity (r > 0.990), precision (coefficients of variation ranged from 0.1 to 2.0%), specificity (similar retention times and spectra in all samples) and recoveries (ranged from 89.2 to 104.9%). The newly developed method is invaluable for assessing the energetic homeostasis of red blood cells under diverse conditions, such as in vitro experiments and clinical settings.

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Section: Discussionsupporting

confidence: 85%

A Novel Method for Measuring the ATP-Related Compounds in Human Erythrocytes

Aragón-Martínez

Galicia-Castillo

Isiordia-Espinoza

et al. 2014

Tohoku J. Exp. Med.

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“…The remainder must be supplied from outside, and in our in vitro system at least, from adjacent noninfected red cells. Purine is released from red cells almost exclusively in the form ofhypoxanthine (23,24), and is thus susceptible to oxidation by xanthine oxidase present in the medium. Failure of 1 x 10-7 M chloroquine to abolish parasite growth is indicative of chloroquine resistance (31).…”

Section: Resultsmentioning

confidence: 99%

“…ever, how the purine needs of the replicating parasite can be supplied by hypoxanthine derived from the host cell, since many studies, including our own, have shown that hypoxanthine release from human red cells under physiologic conditions is too slow to match the rate of parasite nucleic acid synthesis (22)(23)(24). During the course of a previous study on the regulation of hypoxanthine turnover in human erythrocytes, we noted that incubation in xanthine oxidase markedly accelerated the rate of ATP catabolism and hypoxanthine release (22).…”

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confidence: 99%

Xanthine oxidase inhibits growth of Plasmodium falciparum in human erythrocytes in vitro.

Berman

Human²,

Freese³

1991

J. Clin. Invest.

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Malaria parasites, unable to synthesize purine de novo, use host-derived hypoxanthine preferentially as purine source. In a previous study (1990. J. Biol. Chem. 265:6562-6568), we noted that xanthine oxidase rapidly and completely depleted hypoxanthine in human erythrocytes, not by crossing the erythrocyte membrane, but rather by creating a concentration gradient which facilitated hypoxanthine efilux. We therefore investigated the ability of xanthine oxidase to inhibit growth of FCR-3, a chloroquine-resistant strain of Plasmodium falciparum in human erythrocytes in vitro. Parasites were cultured in human group O erythrocytes in medium supplemented, as required, with xanthine oxidase or chloroquine. Parasite viability was assessed by uptake of radiolabeled glycine and adenosine triphosphate-derived purine into protein and nucleic acid, respectively, by nucleic acid accumulation, by L-lactate production, and by microscopic appearance. On average, a 90% inhibition of growth was observed after 72 h of incubation in 20 mU/ ml xanthine oxidase. Inhibition was notably greater than that exerted by i0' M chloroquine (< 10%) over a comparable period. The IC5o for xanthine oxidase was estimated at 0.2 mU/ ml, compared to 1.5 X i0' M for chloroquine. Inhibition was completely reversed by excess hypoxanthine, but was unaffected by oxygen radical scavengers, including superoxide dismutase and catalase. The data confirms that a supply of hostderived hypoxanthine is critical for nucleic acid synthesis in P. falciparum, and that depletion of erythrocyte hypoxanthine pools with xanthine oxidase offers a novel approach to treatment of chloroquine-resistant malaria infection in humans. (J.

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“…The dashed arrow represents a pathway with no gene yet identified. This figure was modified from reference 39. 0.6 Ϯ 0.2 M) (24), is the primary product of purine catabolism within red blood cells (5,8), is transported across the red blood cell membrane (31), and is effluxed to the outer surface of red blood cells (6). A common phenotype of relapsing fever spirochetes is their adherence to red blood cells during infection in humans and mice (11,15,23).…”

Section: Discussionmentioning

confidence: 99%

Purine Salvage Pathways among Borrelia Species

Pettersson¹,

Schrumpf²,

Raffel³

et al. 2007

Infect Immun

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Genome sequencing projects on two relapsing fever spirochetes, Borrelia hermsii and Borrelia turicatae, revealed differences in genes involved in purine metabolism and salvage compared to those in the Lyme disease spirochete Borrelia burgdorferi. The relapsing fever spirochetes contained six open reading frames that are absent from the B. burgdorferi genome. These genes included those for hypoxanthine-guanine phosphoribosyltransferase (hpt), adenylosuccinate synthase (purA), adenylosuccinate lyase (purB), auxiliary protein (nrdI), the ribonucleotide-diphosphate reductase alpha subunit (nrdE), and the ribonucleotide-diphosphate reductase beta subunit (nrdF). Southern blot assays with multiple Borrelia species and isolates confirmed the presence of these genes in the relapsing fever group of spirochetes but not in B. burgdorferi and related species. TaqMan real-time reverse transcription-PCR demonstrated that the chromosomal genes (hpt, purA, and purB) were transcribed in vitro and in mice. Phosphoribosyltransferase assays revealed that, in general, B. hermsii exhibited significantly higher activity than did the B. burgdorferi cell lysate, and enzymatic activity was observed with adenine, hypoxanthine, and guanine as substrates. B. burgdorferi showed low but detectable phosphoribosyltransferase activity with hypoxanthine even though the genome lacks a discernible ortholog to the hpt gene in the relapsing fever spirochetes. B. hermsii incorporated radiolabeled hypoxanthine into RNA and DNA to a much greater extent than did B. burgdorferi. This complete pathway for purine salvage in the relapsing fever spirochetes may contribute, in part, to these spirochetes achieving high cell densities in blood.

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Oxypurine cycle in human erythrocytes regulated by pH, inorganic phosphate, and oxygen.

Cited by 34 publications

References 29 publications

A Novel Method for Measuring the ATP-Related Compounds in Human Erythrocytes

A Novel Method for Measuring the ATP-Related Compounds in Human Erythrocytes

Xanthine oxidase inhibits growth of Plasmodium falciparum in human erythrocytes in vitro.

Purine Salvage Pathways among Borrelia Species

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