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At least 19 recordsLinked to original sources
PubMed1976

Studies on the effects of coenzyme A-SH: acetyl coenzyme A, nicotinamide adenine dinucleotide: reduced nicotinamide adenine dinucleotide, and adenosine diphosphate: adenosine triphosphate ratios on the interconversion of active and inactive pyruvate dehydrogenase in isolated rat heart mitochondria.

The content of coenzyme A-SH (CoASH) and acetyl-CoA of suspensions of rat heart mitochondria was stabilized by the addition of DL-carnitine and acetyl-DL-carnitine, in the presence of the respiratory inhibitor rotenone. The mitochondrial content of NAD+ and NADH was similarly stabilized by the addition of acetoacetate and DL-3-hydroxybutyrate, and the content of ADP and ATP was imposed by the addition of these nucleotides to the mitochondrial suspension, in the presence of uncoupling agent and oligomycin, to inhibit ATPase. Under these conditions, mitochondrial CoASH/acetyl-CoA, NAD+/ NADH, and ADP/ATP ratios could be varied independently, and the effect on the interconversion of active and inactive pyruvate dehydrogenase could be studied. Decreases in both CoASH/acetyl-CoA and NAD+/NADH ratios were shown to be inhibitory to the steady state activity of pyruvate dehydrogenase, and this effect is described at three different ADP/ATP ratios and different concentrations of added MgCl2. A new steady state level of activity was achieved within 10 min of a change in either CoASH/acetyl-CoA or NAD+/NADH ratio; the rate of inactivation was much higher than the rate of reactivation under these conditions. Effects of CoASH/acetyl-CoA and NAD+/NADH may be additive but are still quantitatively lesser than the changes in activity of pyruvate dehydrogenase induced by changes in ADP/ATP ratio. The variation in activity of pyruvate dehydrogenase with ADP/ATP ratio is described in the absence of changes in the other two ratios, conditions which were not met in earlier studies which employed the oxidation of different substrates to generate changes in all three ratios.

Acetyl Coenzyme A↗
PubMed1979

Structure of poly(adenosine diphosphate ribose): identification of 2'-[1''-ribosyl-2''-(or 3''-)(1'''-ribosyl)]adenosine-5',5'',5'''-tris(phosphate) as a branch linkage.

Poly([14C]adenosine diphosphate ribose) was synthesized from [14C]NAD+ with calf thymus nuclei. The fraction containing poly(adenosine diphosphate ribose) eluted with 0.22--0.40 M phosphate buffer (pH 6.8) from a hydroxylapatite column, was completely hydrolyzed with venom phosphodiesterase, and was separated by DEAE-Sephadex A-25 column chromatography in 7 M urea. A new compound, which constituted 2% of the products from poly(adenosine diphosphate ribose), was found in addition to the expected products--i.e., 5'-AMP, 2'-(1''-ribosyl)adenosine-5',5''-bis(phosphate), and its derivatives. This compound was identified as 2'-[1''-ribosyl 2''-(or 3''-)(1'''-ribosyl)]adenosine-5',5'',5'''-tris(phosphate). The existence of this compound is evidence of a branching structure of poly(adenosine diphosphate ribose), which was previously thought to be a linear molecule. The content of this compound suggests that the frequency of branching is about 1 per 20--30 adenosine diphosphate ribose residues of high molecular weight poly(adenosine diphosphate ribose).

Chemical Phenomena↗
PubMed1975

Formation of adenosine triphosphate from Pi and adenosine diphosphate by purified Ca-2+-adenosine triphosphatase.

Ca-2+-ATPase purified from sarcoplasmic reticulum of rabbit muscle forms a phsophoeznyme when exposed to inorganic phosphate in the presence of Mg-2+. On addition of ADP and Ca-2+ virtually all of the phosphate bound to the enzyme is transferred to form ATP. It has been shown previously and confirmed by us that (a) the purified ATPase contains one major polypeptide and about 30% phospholipids; (b) on removal of residual detergent by passage through Sephadex the enzyme forms vesicular membranes; and (c) these vesicles are leaky and incapable of accumulating Ca-2+. Our findings therefore indicate that we have observed ATP generation from ADP and P-i without the formation of an ion gradient across a membrane. We propose that the energy derived from ion-protein interaction drives the formation of ATP.

Adenosine Diphosphate↗
PubMed1977

Natural occurence of a biopolymer, poly (adenosine diphosphate ribose).

Evidence for the natural occurrence of poly(adenosine diphosphate ribose) in vivo was obtained using a sensitive radioimmunoassay and poly(adenosine diphosphate ribose) glycohydrolase, which specifically hydrolyzes poly(adenosine diphosphate ribose). Calf thymus, liver, kidney, brain, pancreas and spleen contained poly(adenosine diphosphate ribose). Naturally occurring poly(adenosine diphosphate ribose) in calf thymus is composed of molecules of various chain lengths, like that synthesized by an in vitro system. Calf thymus was estimated to contain about 0.02 microgram/mg DNA of poly(adenosine diphosphate ribose).

Animals↗
PubMed1979

Nitrosourea interaction with chromatin and effect on poly(adenosine diphosphate ribose) polymerase activity.

Poly(adenosine diphosphate ribose) polymerase, a chromatin-bound enzyme, was stimulated 150 to 200% after treatment of HeLa cells with methylnitrosourea (MNU). In contrast, a slight inhibitory effect on enzyme activity was observed after treatment of cells with various concentrations of chloroethylnitrosoureas. To define precisely the differential effects of nitrosoureas on the enzyme activity, their interactions with chromatin substructure were studied. A nonrandom, in vivo alkylation of chromatin DNA by equimolar concentrations of MNU and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) was revealed by digestion of nuclei from drug-treated cells with micrococcal nuclease and DNase I. [methyl-14C]MNU interacted preferentially with the more accessible regions of chromatin, the internucleosome linkers, whereas, the [chloroethyl-14C]CCNU alkylated the nucleosomal core DNA to a greater extent. These two drugs also differed in their extent of covalent modification of histone and nonhistone chromosomal protein. The binding of MNU to histones was greater than of CCNU. CCNU mainly affected nonhistone proteins. This difference in the reactivity of methyl and chloroethyl nitrosoureas with chromatin may relate to their differential effect on poly(adenosine diphosphate ribose) polymerase activity, as well as to their carcinogenic and antitumor properties.

Alkylation↗
PubMed1977

Separation of oligo(adenosine diphosphate ribose) fractions with various chain lengths and terminal structures.

Oligo(adenosine diphosphate ribose) preparations with chain lengths of 3 to 10 adenosine diphosphate ribose units were fractionated according to their chain lengths and their terminal structures by hydroxyapatite column chromatography and then polyacrylamide gel electrophoresis. The peak fractions from the hydroxyapatite column were each separated into two distinct subfractions by gel electrophoresis. The two subfractions were found to differ in chain length and terminal structure. A linear correlation was observed between the mobility and the logarithm of the chain length of oligo(adenosine diphosphate ribose) on gel electrophoresis, irrespective of the terminal structure.

Alkaline Phosphatase↗
PubMed1976

Adenosine diphosphate binding to sodium-plus-potassium ion-dependent adenosine triphosphatase. The role of lipid in the nucleotide-potassium ion interplay.

Delipidated dogfish rectal-gland Na++K+-ATPase (Na++K+-dependent adenosine triphosphatase), almost devoid of hydrolytic activity, is able to bind about 2nmol of ADP/mg of protein. The "affinity" of delipidated enzyme for ADP is not affected by K+ in concentrations that greatly decrease the "affinity" of native Na++K+-ATPase. The K+-sensitivity of the ADP binding is in part restored by relipidation with dioleoyl phosphatidylcholine.

Adenosine Diphosphate↗
PubMed1979

Nuclear protein modification and chromatin substructure. 3. Relationship between poly(adenosine diphosphate) ribosylation and different functional forms of chromatin.

The relationship between poly(adenosine diphosphate) ribosylation of nuclear proteins and functionally different forms of chromatin from mid-S-phase HeLa nuclei was investigated. The major observations emerging from this study were that unique nonhistone proteins were modified in mid-S-phase HeLa nuclei. The major acceptor for poly(adenosine diphosphate-ribose) [poly(ADP-Rib)] was an internucleosomal nonhistone protein (protein C; 125 000 molecular weight). Histones H3, H1, H2b, and H2a but not H4 were ADP-ribosylated in S-phase nuclei. Chromatin fragments preferentially released by micrococcal nuclease were enriched in nonhistone proteins, poly(ADP)-ribosylated nuclear proteins, poly(ADP-Rib) polymerase activity and nascent DNA from the DNA replicating fork. In extended forms of chromatin, contiguous to the DNA replicating fork, poly(ADP-Rib) polymerase was maximally active. However, in chromatin distal to the replicating fork (i.e., more condensed structures), nucleosomal histones and histone H1 were not significantly ADP-ribosylated, and poly(ADP-Rib) polymerase activity was depressed two- to threefold. The data suggest that a subset of nucleosomes in extended regions of chromatin is subject to extensive ADP ribosylation.

Cell Nucleus↗
PubMed1975

Light scattering changes of edetic acid-treated, washed rat platelets: effect of adenosine diphosphate and calcium ion in relation to chilling.

The effe-ts of adenosine diphosphate (ADP) and Ca2+ on platelet morphology were studied in edetic acid (EDTA)-treated, washed platelets of rat by means of light scattering measurement at right angles. ADP caused a transient change of light scattering, which was independent of concentration above 5 muM and of pH between 4 and 10. When the platelets were pretreated with ADP or chilled persistently, Ca2+ also caused another transient change of light scattering. The effect of Ca2+ was abolsihed at pH below 6.5. The velocity of both ADP- and Ca2+-induced response was dependnet on temperature, and the magnitude was reduced by metabolic inhibitors and SH-blocking agents. Adenosine triphosphate (ATP) competitively inhibited the ADP-induced response, but not the Ca2+-induced one. The response to Ca2+ of the control and chilled platelets was compared by scanning electron microgram. Apparent similarity of the effect of chilling on membrane structure to that of ADP was suggested.

Adenosine Diphosphate↗
PubMed1975

The effects of adenosine triphosphate and adenosine diphosphate on transmission at the rat and frog neuromuscular junctions.

1 The effects of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) were investigated on evoked end-plate potentials (e.p.ps) and on miniature end-plate potentials (min. e.p.ps) recorded from muscle fibres of the rat diaphragm and the frog sartorius.2 ATP and ADP decreased the quantum content of the e.p.ps and the frequency of the min. e.p.ps. The maximum effects produced by the two substances were similar.3 The potency of ATP was found to be similar to that of adenosine. In the presence of adenosine, in a concentration producing its maximum effect, the addition of ATP had no further effect. This is compatible with the idea that ATP acts in the same way as adenosine.

Adenosine↗
PubMed1975

Adenosine diphosphate effect on contractility of human muscle actomyosin: inhibition by ethanol and acetaldehyde.

Magnesium adenosine triphosphate (Mg-2+-ATP) is known to produce dissociation of muscle actin and myosin in vitro, while its hydrolysis leads to reassociation. The interaction of purified actin and myosin from human muscle, in the presence of Mg-2+-ATP, was stimulated by minute amounts of adenosine diphosphate (ADP), a product of ATP hydrolysis. By contrast, the dissociation of the actomyosin complex was inhibited by ADP. These data suggest that ADP serves to modulate muscle contraction. Ethanol and its primary metabolite, acetaldehyde, inhibited these effects of ADP. The inhibition was reversible when the preparations were freed of these compounds. The effects of ethanol and acetaldehyde on the response of actomyosin to ADP may play a role in the pathogenesis of alcoholic myopathy and cardiomyopathy.

Acetaldehyde↗
PubMed1978

Pseudomonas aeruginosa exoenzyme S: an adenosine diphosphate ribosyltransferase distinct from toxin A.

Pseudomonas aeruginosa exoenzyme S is an adenosine diphosphate ribosyltransferase distinct from Pseudomonas toxin A. Exoenzyme S catalyzes the transfer of radioactivity from all portions of radiolabeled NAD+ except nicotinamide. Digestion of the radiolabeled product(s) formed in the presence of [adenine-14C]NAD+ and exoenzyme S with snake venom phosphodiesterase yields only AMP, suggesting that ADP-ribose is present as monomers and not as poly(ADP-ribose). Exoenzyme S does not catalyze the transfer of ADP-ribose from NAD+ to elongation factor 2, as do toxin A and diphtheria toxin, but to one or more other proteins present in crude extracts of wheat germ or rabbit reticulocytes and in partially purified preparations of elongation factor I. The ADP-ribosyltransferase activity of exoenzyme S is distinct from toxin A by several tests: it is not neutralized by toxin A antibody, it is destroyed rather than potentiated by pretreatment with urea, and it is more heat stable. These latter observations and the substrate specificity suggest that exoenzyme S is different from any previously described prokaryotic ADP-ribosyltransferase.

Adenosine Diphosphate Sugars↗
PubMed1978

Bovine thymus poly(adenosine diphosphate ribose) polymerase.

About 1,300-fold purification of poly(adenosine diphosphate ribose) polymerase has been achieved from the extract of bovine thymus with a recovery of 10 to 20%. The final preparation has a purity of 99%, and the enzyme is composed of a single peptide with a molecular weight of 130,000. The purified enzyme required NAD+, Mg2+, a thiol compound, DNA, and histones for full activity. Whereas DNA is essential for activation of the enzyme, histones are not. The observed stimulation of the reaction by histones is shown to be due to masking of the inhibitory effect of contaminating denartured DNA in native DNA preparation. The concentration of DNA required for half-maximal enzyme activity (apparent Km for DNA) is proportional to the concentration of enzyme in the reaction mixture. The minimum estimation of the number of nucleotide pairs of DNA required for half-maximal activation of one enzyme molecule is 220 to 240 for bulk of calf thymus DNA, while the value is 10 for a calf thymus DNA fraction, "active DNA," which was separated from the enzyme fraction in a stage of the purification. These results suggest that the enzyme is activated by binding to a specific site on calf thymus DNA. The apparent Km for NAD+ and the maximum velocity of the enzyme are estimated to be 60 micrometer and 0.91 mumolper min per mg, respectively.

Animals↗
PubMed1978

Formation and characterization of antibody against 2'-(5"-phosphoribosyl)-5' AMP, the monomer form of poly(adenosine diphosphate ribose).

Specific antibody against 2'-(5"-phosphoribosyl)-5'AMP (PR-AMP), a monomer of poly(adenosine diphosphate ribose) (poly(ADP-Rib)), was produced by immunizing a rabbit with PR-AMP coupled to bovine serum albumin (BSA). Antibody against PR-AMP was purified 53-fold from serum by (NH4) 2SO4 precipitation, and BSA-Sepharose 4B, DEAE-cellulose and (PR-AMP)-BSA-Sepharose 4B column chromatographies. Inhibition experiments show that the adenine ring, 5'-phosphate residue and ribose-ribose bond of PR-AMP were essential for the antigenic determinant of PR-AMP. Anti PR-AMP antibody bound, not only with PR-AMP, but also with poly(ADP-Rib) of various chain lengths, while anti poly(ADP-Rib) antibody bound with poly(ADP-Rib) but not with PR-AMP.

Adenosine Monophosphate↗
PubMed1979

Poly(adenosine diphosphate ribose) synthesis during herpes simplex virus infection.

Immediately after infection of baby hamster kidney cells with herpes simplex virus (HSV), cellular DNA synthesis was blocked, while extensive HSV DNA synthesis began. These dramatic alterations of the control mechanisms for these two DNA synthesizing systems were not accompanied by a change in the poly(adenosine diphosphate ribose) polymerase activity.

Animals↗
PubMed1975

Evidence for adenosine diphosphate ribosylation of Ca2+, Mg2+-dependent endonuclease.

The molecular basis for the inhibition of the Ca2+,Mg2+-dependent endonuclease resulting from the formation of poly(adenosine diphosphate ribose) (ADP-Rib) was studies in a simplified system containing purified rat liver or bull semen endonuclease, purified rat liver poly(ADP-Rib) synthetase, [3H]NAD+, and DNA. Poly-(adp-rib) synthetase activity was stimulated when Ca2+, Mg2+-dependent endonuclease was added to the reaction mixture in place of histones, suggesting that the endonuclease can act as an acceptor for ADP-Rib. Evidence was presented to show that the ADP-Rib moiety of [3H]NAD+ was incorporated in the endonuclease fraction. The [3H]ADP-Rib bound to the endonuclease was in the form of monomers and oligomers and not long chain polymers. The present results suggest that the Ca2+,Mg2+-dependent endonuclease was ADP-ribosylated when the endonuclease was incubated with poly(ADP-Rib) synthetase and NAD+.

Adenosine Diphosphate↗