Further studies on the presumed adenine nucleotide storage compound of rat heart

1985 ◽  
Vol 5 (12) ◽  
pp. 1061-1069 ◽  
Author(s):  
Peter S. Fitt ◽  
Borivoj Korecky ◽  
Nishi Sharma
Keyword(s):  
High Resistance ◽  
Alkaline Hydrolysis ◽  
Rat Heart ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Significant Proportion ◽  
Radioactive Substance ◽  
Sudden Rise ◽  
Rat Hearts ◽  
Hydrolysis Of

Further studies on the acid-precipitable radioactive substance formed during perfusion of Langendorff rat hearts with [14C]adenosine have shown that very brief (30 s) ischaemia causes a sudden rise (20–35%) in its level in the tissue which is followed by the steady fall we have previously described. Analysis of the products of alkaline hydrolysis of this compound shows that at least 96% of the radioactivity appears in the form of a mixture of 2′- and 3′-AMP as would be expected for RNA while its relatively high resistance to dilute alkali suggests that it is poly A. Subcellular localization studies indicate that radioactivity enters all compartments of the cell, with maximum label in the nucleus. However, a significant proportion is present in the mitochondria and may be poly A acting as the mitochondrial storage form of adenine nucleotides whose existence we have proposed.

A possible adenine nucleotide storage form in normal and ischaemic rat heart

1985 ◽  
Vol 5 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Peter S. Fitt ◽  
Borivoj Korecky ◽  
Nishi Sharma
Keyword(s):  
Rat Heart ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Radioactive Product ◽  
Rat Hearts

Perfusion of Langendorff rat hearts with [14C]adenosine yields an acid-insoluble, radioactive product whose concentration falls during ischaemia. The properties of the substance show that it is a polyribonucleotide. It is suggested that it may be mitochondrial poly A acting as a storage form of adenine nucleotides.

scholarly journals The molecular structure of a rapidly formed oligomeric adenosine tetraphosphate derivative from rat heart

1986 ◽  
Vol 234 (3) ◽  
pp. 623-627 ◽  
Author(s):  
W L Hutchinson ◽  
P G Morris ◽  
J Mowbray
Keyword(s):  
Molecular Structure ◽  
Rat Heart ◽  
Chromatographic Analysis ◽  
Trichloroacetic Acid ◽  
Adenine Nucleotides ◽  
Specific Radioactivity ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Rapid Equilibrium

The inability to account for large systematic variations with time in soluble adenine nucleotides in perfused rat hearts [Bates, Perrett & Mowbray (1978) Biochem. J. 176, 485-493; Mowbray, Bates & Perrett (1981) FEBS Lett. 131, 55-59; Mowbray, Perrett & Bates (1984) Int. J. Biochem. 16, 889-894] led us to show that the soluble nucleotides are in rapid equilibrium with some hitherto unrecognized trichloroacetic acid/methanol-precipitable highly phosphorylated heteropolymeric form [Mowbray, Hutchinson, Tibbs & Morris (1984) Biochem. J. 223, 627-632]. Selective digestion coupled to chromatographic analysis together with m.s. and 31P-n.m.r. spectrometry have now been used to show that the likely structure for a purified oligomer that is in specific-radioactivity equilibrium with tissue ATP is 3-phospho-[glyceroyl-gamma-triphosphoroyl-5′-adenosine-3′-3- phospho]4 glyceroyl-gamma-triphosphoroyl-5′-adenosine.

Modulation of Mycobacterium tuberculosis DnaA protein–adenine-nucleotide interactions by acidic phospholipids

2002 ◽  
Vol 363 (2) ◽  
pp. 305-311
Author(s):  
Kohji YAMAMOTO ◽  
Syed MUNIRUZZAMAN ◽  
Malini RAJAGOPALAN ◽  
Murty V.V.S. MADIRAJU
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Membrane Phospholipids ◽  
Membrane Bilayer ◽  
Dnaa Protein ◽  
Head Groups ◽  
Nucleotide Interactions ◽  
Acidic Phospholipids ◽  
Hydrolysis Of

The biochemical aspects of the initiation of DNA replication in Mycobacterium tuberculosis are unknown. To understand this process, we overproduced, purified and characterized the recombinant M. tuberculosis DnaA protein. The M. tuberculosis DnaA protein binds the origin of replication (oriC), ATP and ADP, and exhibited weak ATPase activity. ADP, after hydrolysis of ATP, remained strongly associated with DnaA and the exchange of ATP for bound ADP was weak. Vesicles prepared from acidic phospholipids, such as phosphatidylinositol, cardiolipin and phosphatidylglycerol, promoted dissociation of both ADP and ATP, whereas the neutral phospholipid phosphatidylethanolamine did not. The phospholipid-mediated dissociation of ATP was decreased in the presence of the M. tuberculosis oriC, whereas dissociation of ADP was stimulated in the presence of oriC. Acidic phospholipids in micelles, however, were not efficient in dissociating bound nucleotides from DnaA. Together, these results suggest that both polar head groups and membrane bilayer structure play an important role in M. tuberculosis DnaA—adenine-nucleotide interactions. We suggest that initiation of M. tuberculosis oriC involves intimate interactions between DnaA, adenine nucleotides and membrane phospholipids, and the latter helps to ensure that only the ATP form of the DnaA protein interacts continuously with oriC.

Adenine nucleotide synthesis from inosine during normoxia and after ischaemia in the isolated perfused rat heart

1985 ◽  
Vol 63 (9) ◽  
pp. 1159-1164 ◽  
Author(s):  
J. Aussedat ◽  
M. Verdys ◽  
A. Rossi
Keyword(s):  
Rat Heart ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Low Flow ◽  
Nucleotide Synthesis ◽  
Perfused Rat Heart ◽  
Isolated Perfused Rat Heart ◽  
Nucleotide Content ◽  
Glycogen Stores

[14C]inosine in a range of concentrations of 20 μM to 1 mM was administered-to the isolated perfused rat heart for 30 min. The incorporation of the nucleoside into myocardial adenine nucleotides increased for extracellular concentrations of the precursor up to 50 μM, reaching a plateau at 60 nmol∙g−1∙30 min−1 with concentrations ranging between 50 and 200 μM. The supply of 500 μM and 1 mM of inosine induced a further increase in cardiac adenine nucleotide synthesis to about 200 nmol∙g−1∙30 min−1. When supplied during low flow ischaemia (0.5 mL∙min−1, 30 min.), 1 mM of inosine protected the heart against ATP degradation, while 100 μM of inosine was inefficacious. In the presence of 1 mM of inosine on reperfusion the adenine nucleotide content of the heart was similar to that observed in the absence of the nucleoside. The incorporation of [14C]inosine into adenine nucleotides was, in this last condition, below the value measured before ischaemia. Inosine administration was effective in protecting the heart against ischaemic breakdown of glycogen and favoured postischaemic restoration of glycogen stores.

scholarly journals Sabicea brasiliensis Wernham: Antioxidant Activity, Proliferative Effect and Modulation of Vascular Adenine Nucleotides Metabolism

2020 ◽  
pp. 1-10
Author(s):  
Douglas Souza Oliveira ◽  
Mikaelle Costa Correia ◽  
Bruna Juber de Araújo ◽  
Fernanda Cardoso da Silva ◽  
Paula Marynella Alves Pereira Lima ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Cell Viability ◽  
Phenolic Content ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Total Phenolic ◽  
Vascular Cells ◽  
Proliferative Effect ◽  
A7r5 Cells ◽  
Hydrolysis Of

Aims: Study addressed the antioxidant activity (AA) of Sabicea brasiliensis roots crude extract (CE), ethyl acetate (EAF), and hydro-methanolic (HMF) fractions, and its impact on cell viability and adenine nucleotide hydrolysis in vascular A7r5 cells. Materials and Methods: AA of CE, EAF and HMF were determined by the inhibition of the DPPH and ABTS radicals. Total phenolic content was evaluated by Folin-Ciocalteau. Cell viability was determined by MTT assay at different concentrations (62.5; 125; 250 and 500 μg·mL-1) of EAF and HMF after 24, 48 and 72 h. Ectonucleotidase activities were evaluated by colorimetric methods after 48 h EAF or HMF treatment. Results: The highest AA was observed for CE (76%), followed by EAF (46%) and HMF (23%). Phenolic content followed the same pattern. After 48 h, EAF increased A7r5 vascular cells viability by 40%, 40%, 62% and 25% at distinct concentrations, respectively; while HMF augmented it by 50% (500 μg·mL−1). Finally, after 48 h EAF (500 μg·mL−1) decreased about 50% of ATP and ADP metabolism while HMF inhibited 56 and 59% the hydrolysis of NPP substrate (at 125 and 250 μg·mL−1). Conclusion: Study confirmed the high AA of S. brasiliensis, which influences vascular cells proliferation and purines metabolism, pointing to potential cellular pathways that may support the popular use of this plant.

scholarly journals Systematic variations in the content of the purine nucleotides in the steady-state perfused rat heart. Evidence for the existence of controlled storage and release of adenine nucleotides

1978 ◽  
Vol 176 (2) ◽  
pp. 485-493 ◽  
Author(s):  
David J. Bates ◽  
David Perrett ◽  
John Mowbray
Keyword(s):  
Cyclic Amp ◽  
Rat Heart ◽  
Energy Demand ◽  
De Novo ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Purine Nucleotide ◽  
Purine Nucleotides ◽  
Perfused Rat Heart ◽  
Adenine Nucleotide Pool

1. The contents of the major purine nucleotides in the isolated non-working perfused rat heart varied systematically during 80min of perfusion. In particular the amounts of ATP, ADP, GTP, cyclic AMP and cyclic GMP in the well-oxygenated myocardium showed changes ranging from 25 to 60% of the mean concentrations. The apparent periodicity was about 30min for some and about 60min for other nucleotides. 2. These data are in contrast with measurements of parameters reflecting heart performance, which remained constant over this period of perfusion. 3. The ATP/ADP ratio, the cyclic AMP content, the GTP content and the GTP/GDP ratio in the tissue bore a constant relationship to one another, and all showed the same temporal variation. 4. Increasing the energy demand on the heart by administration of bovine somatotropin (1μg/ml) tended to damp the variations, and generally lower the content of all the nucleotides. 5. The total extractable adenine nucleotide pool also showed systematic temporal variations of as much as 1.3μmol/g wet wt. of tissue within 10min. 6. These variations could not be accounted for as inter-conversion with adenosine, other purine nucleotides, nucleosides or purine-degradation products either in the tissue or in the perfusion medium. No evidence was found in this preparation of the purine nucleotide oscillations described by Lowenstein and his co-workers [see Tornheim & Lowenstein (1975) J. Biol. Chem.250, 6304–6314]. 7. Further, the pool size increases cannot be satisfactorily explained by either synthesis de novo or the breakdown of any purine macromolecular species in the cell. Thus it is suggested that an unsuspected substantial storage form of purine nucleotide may exist in heart.

The Platelet of the Newborn Infant – Adenine Nucleotide Metabolism and Release

1980 ◽  
Vol 43 (02) ◽  
pp. 099-103 ◽  
Author(s):  
J M Whaun ◽  
P Lievaart ◽  
Keyword(s):  
Newborn Infant ◽  
Adenine Nucleotide ◽  
Platelet Rich Plasma ◽  
Adenine Nucleotides ◽  
Newborn Infants ◽  
Specific Radioactivity ◽  
Nucleotide Metabolism ◽  
Breakdown Product ◽  
Term Infants ◽  
Adenine Nucleotide Metabolism

SummaryBlood from normal full term infants, mothers and normal adults was collected in citrate. Citrated platelet-rich plasma was prelabelled with 3H-adenine and reacted with release inducers, collagen and adrenaline. Adenine nucleotide metabolism, total adenine nucleotide levels and changes in sizes of these pools were determined in platelets from these three groups of subjects.At rest, the platelet of the newborn infant, compared to that of the mother and normal adult, possessed similar amounts of adenosine triphosphate (ATP), 4.6 ± 0.2 (SD), 5.0 ± 1.1, 4.9 ± 0.6 µmoles ATP/1011 platelets respectively, and adenosine diphosphate (ADP), 2.4 ± 0.7, 2.8 ± 0.6, 3.0 ± 0.3 umoles ADP/1011 platelets respectively. However the marked elevation of specific radioactivity of ADP and ATP in these resting platelets indicated the platelet of the neonate has decreased adenine nucleotide stores.In addition to these decreased stores of adenine nucleotides, infant platelets showed significantly impaired release of ADP and ATP on exposure to collagen. The release of ADP in infants, mothers, and other adults was 0.9 ± 0.5 (SD), 1.5 ± 0.5, 1.5 ± 0.1 umoles/1011 platelets respectively; that of ATP was 0.6 ± 0.3, 1.0 ± 0.1,1.3 ± 0.2 µmoles/1011 platelets respectively. With collagen-induced release, platelets of newborn infants compared to those of other subjects showed only slight increased specific radioactivities of adenine nucleotides over basal levels. The content of metabolic hypoxanthine, a breakdown product of adenine nucleotides, increased in both platelets and plasma in all subjects studied.In contrast, with adrenaline as release inducer, the platelets of the newborn infant showed no adenine nucleotide release, no change in total ATP and level of radioactive hypoxanthine, and minimal change in total ADP. The reason for this decreased adrenaline reactivity of infant platelets compared to reactivity of adult platelets is unknown.Infant platelets may have different membranes, with resulting differences in regulation of cellular processes, or alternatively, may be refractory to catecholamines because of elevated levels of circulating catecholamines in the newborn period.

Influence of medium on alkaline hydrolysis of succinic acid monomethyl and monopropyl esters

1980 ◽  
Vol 45 (11) ◽  
pp. 2873-2882
Author(s):  
Vladislav Holba ◽  
Ján Benko
Keyword(s):  
Succinic Acid ◽  
Kinetic Parameters ◽  
Alkaline Hydrolysis ◽  
Specific Interactions ◽  
Nonaqueous Media ◽  
The Media ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of alkaline hydrolysis of succinic acid monomethyl and monopropyl esters were studied in mixed aqueous-nonaqueous media at various temperatures and ionic strengths. The results of measurements are discussed in terms of electrostatic and specific interactions between the reactants and other components of the reaction mixture. The kinetic parameters in the media under study are related to the influence of the cosolvent on the solvation sphere of the reactants.

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