Characterization of an ATP diphosphohydrolase activity (APYRASE, EC 3.6.1.5) in rat blood platelets

Frassetto, Silvana Soriano; Dias, Renato Dutra; Sarkis, João José Freitas

doi:10.1007/bf00926575

Cited by 72 publications

(50 citation statements)

References 52 publications

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“…The Michaelis constant (K m , app) ( Table 1) calculated by linear regression from the results in Figure 4 was closely similar for ATP and ADP hydrolysis (131 ± 17.4 and 110 ± 29 µM, respectively). It is important to note that a similar K m value for both substrates is also a characteristic of other apyrases described in the literature (15,30). The Sertoli cell cultures were able to hydrolyze other di-and triphosphate nucleosides such as GTP, GDP, ITP and IDP (data not shown).…”

Section: Atp Adp and Amp Hydrolysissupporting

confidence: 67%

“…ATP diphosphohydrolase (apyrase) is an enzyme able to promote the removal of two phosphate groups of ATP but of only one phosphate group of ADP. This enzyme presents divalent cation dependence and can be stimulated by Ca 2+ and Mg 2+ (12,15,30,32). The ecto-5-nucleotidase can also be stimulated by Mg 2+ (14,31) but this activation was lower than the apyrase activation (26.3 ± 5% for the ecto-5-nucleotidase activation and 1490 ± 84% for the apyrase activation in relation to the control).…”

Section: Atp Adp and Amp Hydrolysismentioning

confidence: 99%

“…The extracellular hydrolysis of ATP to adenosine by ectonucleotidases has been reported for several cell types (12)(13)(14)(15)(16)(17)(18)(19)(20). These enzymatic activities can regulate the extracellular concentration of adenine nucleotides and nucleosides modulating their local effects.…”

Section: Introductionmentioning

confidence: 99%

“…Degradation of ATP and other nucleotides occurs through a cascade of cell surface-bound enzymes such as ecto-ATPase (EC 3.6.1.3), ectoapyrase/ATP diphosphohydrolase/NTPDase (EC 3.6.1.5), and ecto-5-nucleotidase (EC 3.1.3.5), resulting in the formation of ADP, AMP and adenosine (21). The presence of apyrase activity has been well demonstrated in a large number of mammalian sources (12,13,15). Apyrase is the enzyme that hydrolyzes ATP and ADP (and other tri-and diphosphate nucleosides) to the monophosphate esters plus inorganic phosphate (Pi), releasing 2 mol Pi/mol ATP and 1 mol Pi/mol ADP.…”

Section: Introductionmentioning

confidence: 99%

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Ectonucleotidase activities in Sertoli cells from immature rats

Casali

Silva

Gelain

et al. 2001

Braz J Med Biol Res

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Sertoli cells have been shown to be targets for extracellular purines such as ATP and adenosine. These purines evoke responses in Sertoli cells through two subtypes of purinoreceptors, P 2Y2 and P A1 . The signals to purinoreceptors are usually terminated by the action of ectonucleotidases. To demonstrate these enzymatic activities, we cultured rat Sertoli cells for four days and then used them for different assays. ATP, ADP and AMP hydrolysis was estimated by measuring the Pi released using a colorimetric method. Adenosine deaminase activity (EC 3.5.4.4) was determined by HPLC. The cells were not disrupted after 40 min of incubation and the enzymatic activities were considered to be ectocellularly localized. ATP and ADP hydrolysis was markedly increased by the addition of divalent cations to the reaction medium. A competition plot demonstrated that only one enzymatic site is responsible for the hydrolysis of ATP and ADP. This result indicates that the enzyme that acts on the degradation of tri-and diphosphate nucleosides on the surface of Sertoli cells is a true ATP diphosphohydrolase (EC 3.6.1.5) (specific activities of 113 ± 6 and 21 ± 2 nmol Pi mg -1 min -1 for ATP and ADP, respectively). The ecto-5-nucleotidase (EC 3.1.3.5) and ectoadenosine deaminase activities (specific activities of 32 ± 2 nmol Pi mg -1 min -1 for AMP and 1.52 ± 0.13 nmol adenosine mg -1 min -1 , respectively) were shown to be able to terminate the effects of purines and may be relevant for the physiological control of extracellular levels of nucleotides and nucleosides inside the seminiferous tubules.

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Section: Atp Adp and Amp Hydrolysissupporting

confidence: 67%

Section: Atp Adp and Amp Hydrolysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ectonucleotidase activities in Sertoli cells from immature rats

Casali

Silva

Gelain

et al. 2001

Braz J Med Biol Res

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“…The active form of ATP that causes membrane permeabilization is a fully ionized tetrabasic ion (or ATP 4 ) that interacts with the unique multimeric P2X7 receptors expressed on endothelium and monocyte-macrophages (50). This nucleotide is a relative inhibitor of NTPDases, as these are divalent cation dependent enzymes (51). Such P2X7 receptors are also stimulated by the nonhydrolyzable ATP analog ATP-γ-S but are unresponsive to UTP (35,52).…”

Section: Purinergic Receptorsmentioning

confidence: 99%

The role of purinergic signaling in the liver and in transplantation: effects of extracellular nucleotides on hepatic graft vascular injury, rejection and metabolism

Beldi

Enjyoji²,

Wu³

et al. 2008

Front Biosci

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Extracellular nucleotides (e.g. ATP, UTP, ADP) are released by activated endothelium, leukocytes and platelets within the injured vasculature and bind specific cell-surface type-2 purinergic (P2) receptors. This process drives vascular inflammation and thrombosis within grafted organs. Importantly, there are also vascular ectonucleotidases i.e. ectoenzymes that hydrolyze extracellular nucleotides in the blood to generate nucleosides (viz. adenosine). Endothelial cell NTPDase1/ CD39 has been shown to critically modulate levels of circulating nucleotides. This process tends to limit the activation of platelet and leukocyte expressed P2 receptors and also generates adenosine to reverse inflammatory events. This vascular protective CD39 activity is rapidly inhibited by oxidative reactions, such as is observed with liver ischemia reperfusion injury. In this review, we chiefly address the impact of these signaling cascades following liver transplantation. Interestingly, the hepatic vasculature, hepatocytes and all non-parenchymal cell types express several components co-ordinating the purinergic signaling response. With hepatic and vascular dysfunction, we note heightened P2-expression and alterations in ectonucleotidase expression and function that may predispose to progression of disease. In addition to documented impacts upon the vasculature during engraftment, extracellular nucleotides also have direct influences upon liver function and bile flow (both under physiological and pathological states). We have recently shown that alterations in purinergic signaling mediated by altered CD39 expression have major impacts NIH Public Access Author ManuscriptFront Biosci. Author manuscript; available in PMC 2010 June 25. Published in final edited form as:Front Biosci. ; 13: 2588-2603. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript upon hepatic metabolism, repair mechanisms, regeneration and associated immune responses. Future clinical applications in transplantation might involve new therapeutic modalities using soluble recombinant forms of CD39, altering expression of this ectonucleotidase by drugs and/or using small molecules to inhibit deleterious P2-mediated signaling while augmenting beneficial adenosine-mediated effects within the transplanted liver. KeywordsTransplantation; Liver; Purinergic Receptors; Bile; CD39; ecto-ATPase; Endothelium; Immunology; Metabolism; NTPDase; Platelet; Vasculature; Review INTRODUCTIONPurinergic signaling comprises release of extracellular nucleotides, stimulation of purinergic receptors and the modulation of nucleotide levels by ectoenzymes. Over the past decade, many advances have been made in the study of purinergic receptors and the regulation of extracellular nucleotide concentrations (1). It is now generally accepted that extracellular nucleotides (e.g. ATP, UTP, ADP), and the derivative nucleosides (e.g. adenosine from ATP), are released in a regulated manner by cells to provide the primary components for purinergic responses (2). Specific nucleo...

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Thyroid hormones alter the adenine nucleotide hydrolysis in adult rat blood serum

et al. 2010

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The effects of ATP, ADP, and adenosine in the processes of platelet aggregation, vasodilatation, and coronary flow have been known for many years. The sequential hydrolysis of ATP to adenosine by soluble nucleotidases constitutes the main system for rapid inactivation of circulating adenine nucleotides. Thyroid disorders affect a number of biological factors including adenosine levels in different fractions. Then, we intend to investigate if the soluble nucleotidases responsible for the ATP, ADP, and AMP hydrolysis are affected by variations in the thyroid hormone levels in blood serum from adult rats. Hyperthyroidism was induced by daily intraperitoneal injections of L-thyroxine (T4) (2.5 and 10.0 μg/100 g body weight, respectively) for 7 or 14 days. Hypothyroidism was induced by thyroidectomy and methimazole (0.05%) added to their drinking water during 7 or 14 days. The treatments efficacy was confirmed by determination of hemodynamic parameters and cardiac hypertrophy evaluation. T4 treatment predominantly inhibited, and hypothyroidism (14 days after thyroidectomy) predominantly increased the ATP, ADP, and AMP hydrolysis in rat blood serum. These results suggest that both excess and deficiency of thyroid hormones can modulate the ATP diphosphohydrolase and 5'-nucleotidase activities in rat blood serum and consequently modulate the effects mediated by these enzymes and their products in vascular system.

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Characterization of an ATP diphosphohydrolase activity (APYRASE, EC 3.6.1.5) in rat blood platelets

Cited by 72 publications

References 52 publications

Ectonucleotidase activities in Sertoli cells from immature rats

Ectonucleotidase activities in Sertoli cells from immature rats

The role of purinergic signaling in the liver and in transplantation: effects of extracellular nucleotides on hepatic graft vascular injury, rejection and metabolism

Thyroid hormones alter the adenine nucleotide hydrolysis in adult rat blood serum

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