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PubMedDate not supplied

[Content of adenine nucleotides and creatinephosphate in brain, myocardium, liver and skeletal muscle under combined action of hypercapnia, hypoxia and cooling].

Cooling of rats under conditions of hypercapina and hypoxia induced no changes in the content of adenine nucleotides in the brain and skeletal muscles and decreased their concentration in the liver and myocardium. The content of creatine phosphate increased in the brain, but had no changes in the other tissues. 48 hours after cooling the amount of adenine nucleotides in the brain was higher as compared with the initial values, that was due to an increase in the ATP concentration; in the other tissues the contents of adenine nucleotides did not differ from that of the intact rats. The repeated action (48 hours after the first influences) caused no changes in the contents of adenine nucleotides in skeletal muscles and decreased them in the myocardium and liver. In the brain their amount and the content of creatinephosphate were increased as related to the intact rats. In the brain and myocardium the level of NADPH decreased after the first action and 48 hours after impact it restored up to the inital values. After repeated impact the level of NADPH in the brain restored up to initial values, in the myocardium it was increased.

Adenine Nucleotides↗
PubMed1988

Postnatal development of rat liver mitochondrial functions. The roles of protein synthesis and of adenine nucleotides.

It has been proposed that the acquisition of efficient energy-transducing mitochondria after birth is mediated by an ATP-dependent mechanism "that causes the rapid maturation of mitochondria without requiring either transcription or translation" (Pollak, J. K., and Sutton, R. (1980) Trends Biochem. Sci. 5, 23-27). Investigation of developmental changes in rat liver mitochondria during the first 6 postnatal h showed that fetal mitochondria had low State 4, State 3, and uncoupled rates of respiration, inefficient coupling between respiration and phosphorylation, and low membrane potentials and proton electrochemical gradients under State 4 conditions. In contrast, hepatic mitochondria from 1-h-old neonates showed increased respiratory control and ADP/O ratios and adult proton electrochemical gradient and membrane potential values. In parallel with these changes, mitochondria became enriched in adenine nucleotides and underwent a 50% reduction in matrix volume. During the first postnatal hour, an increase in mitochondrial succinic dehydrogenase, cytochrome c oxidase, and F1-ATPase activities takes place in the neonatal liver concurrent with a preferential postnatal increase in the in vivo rates of protein synthesis for mitochondrial proteins. In particular, the amount of F1-ATPase increased from 109 +/- 9 to 206 +/- 5 ng/microgram of mitochondrial protein in the first hour of postnatal life. Inhibitors of cytosolic protein synthesis present during the first 2 h of life blocked the postnatal increase in respiratory control and ADP/O ratios, succinic dehydrogenase activity, and F1-ATPase content; but they had no effect on the increase in adenine nucleotide concentrations and mitochondrial volume contraction. This indicates that the acquisition of an efficient coupling between respiration and phosphorylation is dependent on de novo protein synthesis and cannot be brought about by the postnatal increase in adenine nucleotides. The increase of State 4 and uncoupled rates of respiration during the first 2 postnatal h was resistant to protein synthesis inhibitors. We suggest that the postnatal increase in these parameters is due to the reduction of mitochondrial volume occurring during that time, which, in turn, may be triggered by the concurrent enrichment in adenine nucleotides.

Adenine Nucleotides↗
PubMed1986

A new synthetic pathway to adenine-2-d, 9-alkyladenine-2-d, adenosine-2-d, and 2'-deoxyadenosine-2-d.

Unambiguous assignments of the purine ring protons in the NMR spectra of adenine (Ia) and its 9-substituted derivatives (Ib-f) have been made by comparison with those of the isotopically labeled adenines VIIIa-f. 9-Alkyl-2-deuterioadenines (VIIIb-d), adenosine-2-d (VIIIe), and 2'-deoxyadenosine-2-d (VIIIf) were synthesized from the 9-substituted adenines Ib-f through cyclization of the monocyclic intermediates VIb-f with formic acid-d2 or 1-(formyl-d)-2(1H)-pyridone. Hydrolysis of VIIIe with 0.5 N aq. HCl gave adenine-2-d (VIIIa) in 77% yield.

Adenine↗
PubMed1985

[Effect of the adenine level of a culture medium on the frequency of revertants in haploid yeasts].

The frequency of reversion from adenine auxotrophy in the yeast Saccharomyces cerevisiae increases with the decrease of adenine concentration in the medium: for the 8PG-59 strain (a ade2-192 rad2) the reversion frequency is 1.7 X 10(-8), 3.2 X 10(-6) and 1.8 X 10(-5) per cell division, the initial adenine concentrations being 10, 1 and 0.1 mg/l, respectively. An increase of the reversion frequency with the culture age in the stationary phase of growth is demonstrated using an improved method of registration of revertants, with the initial concentration of 0.1 mg/l of adenine in the medium. The reversion frequency was 9.1 X 10(-7) on the 7th day, 1.8 X 10(-6) on the 10th day and 1.8 X 10(-5) on the 14th day.

Adenine↗
PubMed1985

Changes in morphology of endocytotic vesicles in cardiac capillary endothelial cells and myocytes of rats after treatment with adenine and AMP.

Isolated rat hearts were perfused with media containing no additions (sham), adenine, or AMP to determine if adenine or AMP would affect post-ischaemic myocyte ultrastructure. The most significant change induced by both adenine and AMP was a dramatic increase in the number and size of endocytotic vesicles apparent in capillary endothelia and myocytes. This observation suggests endocytosis as a possible transport mechanism for AMP or adenine, or other large polar molecules including purine nucleotide precursors, from the coronary circulation across capillary endothelia and into myocytes.

Adenine↗
PubMedDate not supplied

[Interaction of formaldehyde with nucleic acids and their structural components in the presence of amines. II. Structure of adenine derivatives formed in the reaction with formaldehyde and primary amine].

Two products of modified adenine have been isolated from reaction of adenine with a mixture of formaldehyde and methylamine; their structures have been demonstrated by UV, 1H NMR and mass spectra data. The formal scheme of reaction can be described as simultaneous or sequential cycloaddition of dimethylol derivatives of methylamine to two reaction's positions of the adenine residue. This results in the formation of a new partly or completely hydrogenated six-membered 1,3,5-triazine cycle which has the atoms of adenine nitrogen in its 1,3-positions and nitrogen of methylamine in 5-position. This is used as a model for discussing the peculiarities of DNA-formaldehyde interaction in the presence of amine.

Adenine↗
PubMed1985

Adenine therapy in Lesch-Nyhan syndrome.

In a 7-year-old patient with Lesch-Nyhan syndrome (LNS) the 15N excess frequency was determined in the excreted uric acid after oral application of 27 mg 15N glycine/kg body weight, using emission spectrometry. Incorporation of glycine into uric acid was considerably increased in untreated LNS in comparison with the control. This was due to the extremely increased endogenous de novo synthesis of purine. Allopurinol therapy caused only a gradual decrease of uric acid excretion. The pattern of purine excretion changed in favour of the better soluble oxipurines hypoxanthine and xanthine, by competitive inhibition of xanthine oxidase. In LNS, however, allopurinol had no uricostatic effect. Therapy with adenine is an alternative to influence the de novo synthesis. After adenine application a decrease of the cumulative 15N uric acid excretion occurs and the percentual proportion of 15N uric acid in total 15N excretion decreases. These changes are due to an inhibition of de novo purine biosynthesis. Adenine, however, must be applied in combination with allopurinol in order to avoid the formation of nephrotoxic 2,8-dioxiadenine by xanthine oxidase. Adenine therapy led to an improvement of the clinical course. No side-effects were observed.

Adenine↗
PubMed1979

Effect of sepsis on tissue adenine nucleotide levels.

Tissue adenine nucleotides were measured in rats to determine if there is depletion of energy stores associated with sepsis. Peritonitis was produced by cecal ligation and cecal puncture. At 16 to 24 hours after ligation, rats which were lethargic but still normotensive (late sepsis) and showed clinical and laboratory confirmation of peritonitis-sepsis were stunned by a blow on the head, and small pieces of tissue were removed and frozen. Adenine nucleotides were measured enzymatically. In late sepsis adenosine triphosphate (ATP) levels in liver and kidney decreased significantly; however, no significant decreases were observed in the diaphragm or gastrocnemius muscle. Hydrogen polarograph measurements of hepatic blood flow indicated that flow was decreased markedly at this stage of peritonitis. A second group of rats was prepared in the same manner, except they were studied 10 hours after ligation (early sepsis). Most rats at this stage of sepsis appeared to be only mildly ill; however, blood cultures obtained from six rats so prepared all were positive. These rats did not show any decrease in either hepatic blood flow or tissue adenine nucleotides. Thus the changes in adenine nucleotides observed in late sepsis (lpw-flow septic rats) are similar to those seen during early hemorrhagic shock and suggest inadequate perfusion associated with peritonitis as the cause.

Adenine Nucleotides↗
PubMed1979

A Raman spectroscopic study of the interaction of divalent metal ions with adenine moiety of adenosine 5'-triphosphate.

Raman spectra of ATP at various pH values are affected by addition of equimolar solution of divalent metal ions such as Ca2+, Mg2+, Co2+, Cu2+, and Hg2+. The changes in frequency and intensity have been used to construct models describing the nature of metal-adenine and metal-triphosphate interactions under different conditions. The metal ions are found to co-ordinate the triphosphate group in the entire pH range studies (pH to 12). Calcium (II) and magnesium (II) interact strongly with the phosphate moiety at neutral pH, although a weak interaction with the ring occur at low pH values. Around neutrality, several Raman spectral changes are observed to implicate the interaction of cobalt (II) ion with the five-membered ring of the adenine. The changes in Raman frequency are too small to suggest a direct Co(II)-N7 binding. At least six different Cu(II)-ATP species are identified between pH 3 and 12. At pH approximately 7.0 Raman data are explained better by Cu(II) interacting with N7 simultaneously with the amino group of the adenine ring. However, a Cu(II) binding to N3 at pH 10 to 11 is indicated by the enhancement of the 760 and 1360 cm-1 vibrations. At neutral pH, mercury (II) ion shows a direct coordination at N1 while at low pH with N1 blocked by protonation, mercury (II) does not interact with the adenine moiety.

Adenine↗
PubMed1980

Preservation of red blood cells with purines and nucleosides. III. Synthesis of adenine, guanine, and hypoxanthine nucleotides.

Purine nucleotides of fresh human red cells and of red cells during storage at 4 degrees and 25 degrees C with additions of adenine, guanine, guanosine and inosine were estimated by HPLC. Six nucleotides were found in red cells: ATP, ADP, AMP, GTP, GDP, and IMP. The adenine nucleotides represented 92 per cent of the total purine nucleotides, guanine nucleotides 7 per cent and IMP less than 1 per cent. In red cells stored with adenine the total concentration of purine nucleotides increased to 125 per cent of the normal value. An adenine-free but guanine and guanine + inosine containing medium caused a decrease of the concentration of purine nucleotides by 10 to 20 per cent. When red cells were stored without adding guanine or guanosine the content of the guanine nucleotides decreased from 0.32 to 0.17 mumol/g Hb due to the decrease in the GTP content, but the GDP concentration increased slightly. In CPD-AG blood, however, the concentration of guanine nucleotides increased considerably up to 0.6 mumol/g Hb. IMP was estimated in all investigated stored red cells. In CPD-A and in CPD-AG blood 0.4 mumol/g Hb were produced during 3 weeks of storage, but twice of that in CPD-AI blood. The principles of the synthesis and the degradation of purine nucleotides in stored red cells are discussed in detail.

Adenine Nucleotides↗
PubMed1982

In vivo study of the influence of adenine and guanosine on the erythrocytes of ACD (pH 5.0 and 5.6) preserved blood.

Data are presented for percentage of recovery, survival time (T1/2) and mode of sequestration of erythrocytes from ACD [disodium citrate 95 mmol/l and glucose (C6H12O6 X H2O)] 152 mmol/l or ACD--adenine or adenine + guanosine (pH ranging from 5.0 to 5.6) preserved blood for 35 days at 4-8 degrees C (277-281 K). With the availability of guanosine in 0.25 mmol/l or 0.5 mmol/l final concentration in ACD + 0.25 or 0.5 mmol/l adenine preserved blood a positive effect can be exerted on erythrocyte 24 hrs recovery and survival time (T1/2). This effect is particularly evident when pH of the preservative solution is raised to 5.6. Final concentrations of 0.25 mmol/l adenine and guanosine in ACD preserved blood (whole or packed erythrocytes, pH 5.6, Hct. 0.73 or 0.61) are sufficient to ensure 35 days of storage at 4-8 degrees C (277-281 K).

Adenine↗
PubMed1983

Symbiotic properties of adenine requiring mutants of Rhizobium meliloti strain L5-30.

From the effective and prototrophic Rhizobium meliloti strain L5-30 two auxotrophic mutants were isolated: RM4 and RM221. These two mutants required adenine and adenine with thiamine for their growth, respectively. Both mutants nodulated lucerne plants ineffectively. Electron microscopic observations of the nodule tissue showed that its cells were not occupied by bacteria. Prototrophic revertants and transductants of these mutants showed high symbiotic effectiveness. It is assumed that adenine or adenine and thiamine requirements made impossible release of bacteria from the infection thread.

Adenine↗
PubMed1984

[Physiopathologic modifications in the myocardial levels of adenine nucleotides].

When the equilibrium between energy production and utilization is disrupted in the myocardium, the metabolism of adenine nucleotides is greatly altered. The first alteration is a change in the degree of phosphorylation which induces alterations in the respective amounts of AMP, ADP and ATP. This change, in turn, creates an imbalance between synthesis and degradation of adenine nucleotides. As a consequence, the levels of AMP, ADP and ATP are not restored when physiological conditions are reestablished. The aim of this paper is to describe the alterations of adenine nucleotides which occur in physiopathological conditions (ischemia, hypertrophy) and to discuss the use of the levels of AMP, ADP and ATP as indicators of the metabolic state of the heart. Brief descriptions of the methods used for determinations of concentrations and of the processes of energy transfer and adenine nucleotide synthesis in the myocardium are given.

Adenine Nucleotides↗
PubMed1984

[Effect of papaverine on the absorption and metabolism of 14C- adenosine and 14C-adenine in thymocytes].

Some peculiarities of adenosine and adenine nucleotide metabolism in rat thymocytes were investigated. It was shown that the uptake of labelled adenosine or adenine by thymocytes is markedly inhibited by papaverine due to the decrease of the adenylate kinase activity, on the one hand, and to the acceleration of ATP catabolism and inosine and hypoxanthine release into the environment, on the other. ATP catabolism occurs in a special compartment which in [14C] adenosine and [14C] adenine prelabelled thymocytes has a higher specific radioactivity as compared with the whole cell. In [14C] adenine-prelabelled thymocytes and extracellular medium, papaverine does not influence the content but increases the specific radioactivity of adenosine.

Adenine Nucleotides↗
PubMedDate not supplied

Adenine nucleotides and 2,3-dophosphoglycerate in the erythrocytes during physical exercise and restitution in healthy subjects.

The reported investigations were carried out in 6 young (20 years old) healthy males who performed a 10-minute exercise on a Monark cycle ergometer at workloads increasing the heart rate to 170/minute. Before the exercise, after its termination, and after 30 minutes of restitution the concentrations of adenosine-5' triphosphate, adenosine-5' diphosphate, adenosine-5' monophosphate, 2,3-diphosphoglycerate, nicotinamide-adenine dinucleotide and nicotinamide-adenine dinucleotide phosphate were assayed in erythrocytes. After the end of exercise a non-significant increase in ATP concentration and a non-significant decrease of 2,3-DPG were found in the erythrocytes. The concentrations of ADP and AMP were lower than at rest, both, after the end of exercise and after 30 minutes of restitution (p less than 0.05). The concentrations of nicotinamide-adenine dinucleotide and nicotinamide-adenine dinucleotide phosphate decreased after exercise (p less than 0.05) fell even more after 30 minutes of restitution (p less than 0.05).

Adenine Nucleotides↗
PubMed1995

The distribution of electron trapping in DNA: one-electron-reduced oligodeoxynucleotides of adenine and thymine.

A series of single- and double-stranded oligodeoxynucleotides of adenine and thymine, 8 to 12 nucleotides in length, were one-electron-reduced at 10 K in a > 8 M LiCl/H2O glass. The Q-band electron paramagnetic resonance (EPR) spectra of these radicals show that thymine is the dominant trapping site for mobile electrons in these oligomers. The spectra of the reduced oligomers in the series pd(AnT10-n).pd(A10-nTn) with n = 5-->10 showed a trend which is interpreted as either an increase in the probability of trapping at an adenine base in tracks of adenine > 7 base pairs in length, or the presence of different protonated states of the one-electron-reduced bases due to the adoption of a different conformational state for longer tracks of adenine, or a combination of these two possibilities. Analysis of the trends in the EPR spectra of the radicals as a function of sequence using multicomponent analysis is presented.

Adenine Nucleotides↗
PubMed1994

Opposing adenine nucleotide-dependent pathways regulate guanylyl cyclase C in rat intestine.

Opposing adenine nucleotide-dependent pathways regulating guanylyl cyclase C (GC-C) in rat intestinal membranes have been identified and characterized. ATP analogues substituted in the 2-position were potent inhibitors of basal and Escherichia coli heat-stable enterotoxin (ST)-stimulated GC-C, independent of the metal cation cofactor present. Inhibition of GC-C was associated with large changes in Vmax but only small changes in the S0.5, suggesting a noncompetitive mechanism. Also, inhibition of GC-C was associated with a concentration-dependent shift from positive to negative cooperativity when manganese served as the cation cofactor. These data support the existence of a noncompetitive allo steric regulatory mechanism mediating adenine nucleotide-dependent inhibition of GC-C. Adenine nucleotides not substituted in the 2-position potentiated the activation of GC-C by ST in intestinal membranes. The potentiating and inhibitory pathways regulating GC-C enzyme activity were separate and distinct. A specific inhibitor (2-chloroadenosine 5'-triphosphate (2ClATP)), was without effect on the potency of a selective activator (adenosine 5'-O-thiomonophosphate (AMPS)) of GC-C. Similarly, AMPS was without effect on the potency of 2ClATP to inhibit GC-C. These data suggest that adenine nucleotide-dependent activation and inhibition are mediated by independent sites which may modulate the second messenger response of GC-C to ST.

Adenine Nucleotides↗
PubMed1994

Photoaffinity labeling of the adenine binding sites of two Dolichos biflorus lectins.

Two differentially expressed lectins from the legume Dolichos biflorus, the seed lectin and a stem and leaf lectin (DB58), were photoaffinity-labeled at their adenine binding sites using the probe [2-3H]8-azidoadenine. Both heteromeric subunits I and II of the seed lectin and alpha and beta of DB58 were specifically labeled. This result, combined with the adenine binding site stoichiometries of two identical sites/seed lectin tetramer or one site/DB58 dimer, indicates that the adenine binding site resides at a heterologous subunit interface. Three radiolabeled peaks from seed lectin and one from DB58 were isolated from chymotryptic digests of the labeled lectins by reverse phase chromatography at pH 7.0. From these four peaks, six unique peptide sequences were determined. When aligned with the concanavalin A sequence, four of these peptides map to three loops in the metal binding domain of concanavalin A. The remaining two sequences represent carboxyl-terminal peptides unique to the D. biflorus lectins which may extend to the putative binding site from adjacent, heterologous subunits. It thus appears that the adenine binding sites of these D. biflorus lectins are within the metal binding domain and adjacent to the carbohydrate binding site.

Adenine↗