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PubMed1991

[Inhibiting effect of a pyrophosphate-dentifrice on calculus formation].

Anticalculus dentifrices containing pyrophosphate salts have been shown to reduce calculus formation. The purpose of this double-blind, cross-over study was to compare the effects of a pyrophosphate dentifrice with a placebo on supragingival calculus formation in highly calculus-prone subjects. 60 volunteers completed a compliance period during which meticulous full-mouth scaling was performed. Subjects were randomly assigned either to placebo (F-Antibelag Gel) or to the test group (F-Antibelag Gel + K4P2O7/Na4P2O7). Participants were told to brush twice daily with their assigned dentifrice, use only the brushes provided and to abstain from any other oral hygiene procedures. After a three month period a second full-mouth scaling was performed, and according to the cross-over design of this study the participants used the alternative placebo or, respectively, dentifrice for another three months. Baseline scores and control scores after 1, 2 and 3 months were obtained using the Volpe-Manhold-Index and the Marginal-Line-Calculus-Index. A micromorphological SEM Calculus Index was introduced using replicas from interdental areas of mandibular incisors (score 0-3). Both test groups showed significantly less accumulation of supragingival calculus of 25.5% (VMI) and 19.5% (MLCI) and significantly less SEM detectable calculus (24%) with the pyrophosphate dentifrice than with the placebo. It is concluded that the test dentifrice inhibits the formation of calculus.

Adult↗

PubMed1976

[Extramitochondrial energy dependent synthesis of inorganic pyrophosphate in yeasts].

In yeast Saccharomyces N.C.Y.C. 644SU3 the simplest energy donor, inorganic pyrophosphate, can be formed not only in the processes coupled with the respiratory chain, but also under conditions when mitochondrial synthesis of the compound is inhibited (glucose repression, anaerobiosis). Stimulation of inorganic pyrophosphate formed after exogeneous addition of glycolytic system components and inhibition studies suggest that under those conditions the non-mitochondrial energy-dependent formation of inorganic pyrophosphate is due to glycolytic phosphorilation.

Adenosine Triphosphate↗

PubMed1976

99m Technetium-pyrophosphate scintiphotography in bone sarcoidosis.

Comparative studies between routine roentgenograms and scintiphotographs using 99mTc-pyrophosphate, of the hands and feet are documented in three cases of bone sarcoidosis. All the abnormal roentgenographic findings were also detected by 99mTc-pyrophosphate bone imaging. However, several areas of increased radiopharmaceutical uptake were found in areas with normal roentgenographic studies. These results suggest that the 99mTc-pyrophosphate bone scintiphotographs might be more sensitive than radiographs in the localization of the bone involvement in sarcoidosis.

Adult↗

PubMedDate not supplied

[The properties of [omega(3-acetylpyridinio)-n-alkyl]adenosine pyrophosphates, structural analogs of the coenzyme NAD (author's transl)].

[omega-(3-Acetylpyridinio)-n-alkyl]adenosine pyrophosphates are coenzyme analogs of NAD. The adenosine pyrophosphate moiety and the 3-acetylpyridine ring of the analogs are connected by n-alkyl chains of different lengths (ethyl--hexyl). The analogs form strong dissociating complexes with lactate dehydrogenase. The complex formation is predominantly achieved by interaction of the ADP moiety with its respective binding domain at the active site. The redox potentials of the analogs and NAD are of similar magnitude. The coenzyme function of the analogs depends upon the length of the hydrocarbon chain. Lactate dehydrogenase and alcohol dehydrogenases from yeast and horse liver do not catalize hydrogen transfer from their substrates to any other alkyl analog but [4-(3-acetylpyridinio)-n-butyl]adenosine pyrophosphate, aldehyde dehydrogenase from horse liver catalizes hydrogen transfer from acetaldehyde to the pentyl derivative and glyceraldehyde-3-phosphate dehydrogenase catalizes hydrogen transfer to both analogs. In no case, hydrogen transfer from or to one of the 3-acetylpyridine-n-alkyl analogs proceeded with a velocity comparable to NAD or its 3-acetylpyridine analog. The results show that the nicotinamide bound ribose in NAD is involved in the binding and the activation of the coenzyme.

Mathematics↗

PubMed1990

[Chemical reactions in double-stranded nucleic acids. IX. Directed introduction of substituted pyrophosphate bonds into DNA structure].

An effective synthesis of oligodeoxyribonucleotides containing a substituted pyrophosphate bond in the definite position of the sugar-phosphate backbone has been developed by template-directed condensation of two heptanucleotides. One of them containing 5'-phosphate group to be activated and 3'-phosphate group of the other being substituted with ethoxy-, buthylamino-, morpholino- or ethyl glycinate residues. Water-soluble carbodiimide (EDAC) proved to be more efficient in the phosphate group activation than N-hydroxybenzotriazole ester (yields of substituted pyrophosphates 35-80 and 10-15% respectively). The substituted pyrophosphate bong is quite stable in neutral aqueous solution. Mild conditions of selective cleavage of this bond yielding the initial oligonucleotides were found.

Base Sequence↗

PubMed1990

Pyrophosphate-dependent phosphofructokinase. Conservation of protein sequence between the alpha- and beta-subunits and with the ATP-dependent phosphofructokinase.

Full-length cDNA clones for the alpha- and beta-subunits of pyrophosphate-fructose 6-phosphate 1-phosphotransferase have been isolated from a cDNA expression library derived from potato tuber poly(A)+ RNA. The nucleotide sequences indicate that the alpha- and beta-subunits are related with about 40% of amino acid residues being identical. A comparison of the deduced amino acid sequences of both subunits of this enzyme with that of the major ATP-dependent fructose 6-phosphate 1-phosphotransferase from Escherichia coli (Shirakihara, Y., and Evans, P. R. (1988) J. Mol. Biol. 204, 973-994) showed little homology between the proteins except for regions involved in the binding of fructose 6-phosphate/fructose, 1,6-bisphosphate and possibly between regions binding pyrophosphate and the beta- and gamma-phosphates of ADP/ATP. A comparison of the derived secondary structures of the two subunits of the PPi-dependent enzyme with the known secondary structure of the E. coli ATP-dependent enzyme indicated that the overall structure of these enzymes is similar. These data suggest that catalytic activity resides on the beta-subunit of the pyrophosphate-dependent enzyme.

Adenosine Triphosphate↗

PubMed1990

[High-molecular polyphosphates and pyrophosphate in cyclosporin- producing Tolypocladium sp. and their role in the processes of growth and antibiotic synthesis].

The contents of high-energy phosphorous compounds, i.e. three fractions of polyphosphates, pyrophosphate, and ATP were determined in isogenic strains of Tolypocladium sp. differing in cyclosporine production levels. The content of polyphosphates was 1 to 2 orders of magnitude greater than that of pyrophosphate or ATP and did not depend on the strain productivity. During the period of the mycelial intensive growth and at the beginning of antibiotic synthesis, the level of polyphosphates lowered 2-3-fold and the content of pyrophosphate markedly decreased as well. The activities of polyphosphatase and pyrophosphatase during the culture growth and cyclosporine biosynthesis was higher in the highly productive strain.

Cyclosporins↗

PubMed1979

[Myocardial scintigraphy with pyrophosphate-99mTc in transitory myocardial ischemia in chronic ischemic heart disease].

Scintigraphy of the myocardium with pyrophosphate-99mTc was used in the examination of 45 patients with chronic ischemic heart disease and 3 patients with vegetovascular dystonia. A direct dependence of the character of the scintigram on the anginous attack was revealed. Accumulation of pyrophosphate-99mTc in the myocardium was observed in all patients with the agent injected just before the attack, during the attack or in the first 8 hours after it. Pyrophosphate-99mTc accumulation in the myocardium demonstrated on the scintigrams of the myocardium was less intense but more diffuse and extensive in chronic ischemic heart disease than in the focus of acute myocardial infarction.

Adult↗

PubMed1987

Drug-induced Ca2+ release from isolated sarcoplasmic reticulum. I. Use of pyrophosphate to study caffeine-induced Ca2+ release.

A demonstration is made of pyrophosphate's use as a precipitating anion in studies of Ca2+ release from isolated sarcoplasmic reticulum (SR). Not only does pyrophosphate speed up the rate at which Ca2+ can be preloaded into SR, but it also allows the accumulated Ca2+ to be released in response to agents such as caffeine. Because so much Ca2+ can be preloaded into SR with pyrophosphate present, more experiments can be performed with a given amount of SR material, and even rapid Ca2+ release rates (greater than 1 mumol/mg X min) are maintained for many seconds. These rates can easily be quantified using conventional spectrophotometric and isotopic methods, without the need for expensive rapid mixing equipment. Caffeine-induced Ca2+ release is exhibited by triadic and terminal cisterna SR subfractions but not by light SR. Caffeine specifically increases the rate of unidirectional 45Ca2+ efflux. This increased efflux is blocked by ruthenium red at submicromolar concentrations and by tetracaine, 9-aminoacridine, or Ba2+ at submillimolar concentrations.

Aminacrine↗

PubMed1987

The characteristics of pyrophosphate: D-fructose-6-phosphate 1-phosphotransferases from Sansevieria trifasciata leaves and Phaseolus coccineus stems.

Three different molecular forms of pyrophosphate-dependent phosphofructokinase have been isolated: one from Sansevieria trifasciata leaves and two from Phaseolus coccineus stems. The form isolated from S. trifasciata has the molecular weight of about 115,000. The apparent molecular weights for the two forms from mung bean were approximately 220,000 and 450,000. All three forms have the same pH optima, an absolute requirement for Mg2+ ions both in the forward and reverse reaction, but differ in their sensitivity toward fructose 2,6-bisphosphate. Kinetic properties of the partially purified enzymes have been investigated in the presence and absence of fructose 2,6-bisphosphate. Pyrophosphate-dependent phosphofructokinase from S. trifasciata exhibited hyperbolic kinetics with all substrates tested. The saturation curves of the enzyme (form A) from mung bean for pyrophosphate, fructose 6-phosphate and fructose 1,6-bisphosphate were sigmoidal in the absence of fructose 2,6-bisphosphate. In the presence of fructose 2,6-bisphosphate these kinetics became hyperbolic.

Fabaceae↗

PubMed1975

Formation and in-vivo-distribution of different 99mTc-Sn-pyrophosphate complexes.

The formation of two different 99mTc-Sn-pyrophosphate complexes was determined by evaluation of their in vivo distribution in rats. It was found that formation of a 2 : 2 Sn : PyP complex, which is bone seeking, is depending as well on the pyrophosphate as on the hydrogen ion concentration in the equilibrium. On the contrary, formation of a 2 : 1 Sn : PyP complex, which shows no bone affinity but concentrate in the kidneys, is hydrogen ion independent and occurs even at very low pyrophosphate concentrations. The probable structure of these complexes is discussed.

Animals↗

PubMedDate not supplied

[Interaction of EcoRII restriction and modification enzyme with synthetic DNA fragments. IV. DNA duplexes with phosphoamide and pyrophosphate internucleotide bonds--the substrates for the study of single-strand breaks].

A set of DNA duplexes with repeated EcoRII, EcoRI and AluI restriction endonuclease recognition sites in which EcoRII scissile phosphodiester bonds were replaced by phosphoramide or uncleavable pyrophosphate bonds have been synthesized. Endonuclease EcoRII was found not to cleave the substrate at the phosphoramide bond. The substrates containing non-nydrolysable pyrophosphate or phosphoramide bonds in one of the chains of EcoRII recognition sites were used to show that this enzyme is able to catalyze single-strand scissions. These scissions occur both in dA- and dT-containing chains of the recognition site. Endonuclease EcoRII interacts with both strands of the DNA recognition site, each of them being cleaved independently on the cleavage of the other. Synthesized DNA-duplexes are cleaved specifically by EcoRI and AluI endonucleases, this cleavage being retarded if the modified bonds are in the recognition site (EcoRI) or flank it (AluI). For EcoRII and AluI this effect is more pronounced in the case of substrates with pyrophosphate bonds than with the phosphoramide ones.

Autoradiography↗

PubMed1987

Squalene synthetase. Solubilization and partial purification of squalene synthetase, copurification of presqualene pyrophosphate and squalene synthetase activities.

Squalene synthetase (farnesyldiphosphate:farnesyldiphosphate farnesyltransferase, EC 2.5.1.21) is an intrinsic microsomal protein that catalyzes the synthesis of squalene from farnesyl pyrophosphate via the intermediate presqualene pyrophosphate. We have solubilized this enzyme from yeast with a mixture of the detergents N-octyl beta-D-glucopyranoside and Lubrol PX. Approximately 50-fold purification of the solubilized activities has been achieved by chromatography on DEAE-cellulose and hydroxylapatite and by isoelectric focusing. The most highly purified preparation has one major band of protein with a molecular weight of 53,000 as estimated by electrophoresis under denaturing conditions. The enzyme may also have been modified by proteolysis during isolation since a 47,000 molecular weight species was also found. The two activities, presqualene pyrophosphate synthetase and squalene synthetase, copurified during isolation.

Chromatography, DEAE-Cellulose↗

PubMed1970

Biosynthesis of presqualene pyrophosphate by liver microsomes.

Microsomes from rat liver have been shown to synthesize a squalene precursor from farnesyl pyrophosphate. This intermediate is identical with presqualene pyrophosphate, a 30-carbon cyclopropane containing pyrophosphate ester that had previously been isolated from yeast. The squalene precursor was found to be tightly, but not covalently, bound to microsomes.

Alkaline Phosphatase↗

PubMed1984

[A new type of DNA modification. Specific introduction of 3'-5'-pyrophosphate internucleotide bonds].

Novel compounds--modified DNA-duplexes containing 3'-5'-pyrophosphate internucleotide bonds--have been synthesized. The synthesis was carried out by means of chemical template-guided polycondensation of 3'-5'-diphosphate of decanucleotide pTGGCCAAGCTp, which forms DNA-like duplexes as a result of self-association. 1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide was used as a condensing agent. Almost quantitative yield of polymer products was achieved by incubation of the reaction mixture for 72 hours. The pyrophosphate type of the internucleotide bonds was confirmed by complete cleavage of these polymers by trifluoroacetic anhydride. The interaction of DNA-duplexes, containing the 3'-5'-pyrophosphate bonds, with restriction endonucleases BspI, HindIII and AluI was studied. BspI and HindIII were able to hydrolyze modified duplexes giving corresponding decanucleotides, whereas AluI failed to split the duplexes.

Chemical Phenomena↗

PubMed1980

A novel reaction catalyzed by unadenylylated glutamine synthetase from Escherichia coli. AMP-dependent synthesis of pyrophosphate and L-Glutamate from orthophosphate and L-glutamine.

The unadenylylated, manganese form of glutamine synthetase (L-glutamate: ammonia ligase (ADP forming), EC 6.3.1.2 from Escherichia coli catalyzes a novel, AMP-dependent (reversible) synthesis of pyrophosphate and L-glutamate from orthophosphate and L-glutamine: Formula (See Text). The hydrolysis of the L-glutamine amide bond is coupled to the stoichiometric synthesis of pyrophosphate, although as PPi accumulates, additional hydrolysis of L-glutamine occurs in a secondary reaction catalyzed by the [manganese x enzyme x AMP x PPi] complex. The synthesis of PPi probably occurs at the subunit catalytic site in the positions normally occupied by the beta, gamma-phosphates of ATP. To promote PPi synthesis, AMP apparently binds to the subunit catalytic site rather than to the allosteric inhibitor site; equilibrium binding results suggest that Pi directs the binding of AMP to the active site. In this reaction, Mg2+ will not substitute for Mn2+, and adenylylated glutamine synthetase is inactive. Pyrophosphate is synthesized by the unadenylylated, manganese enzyme at approximately 2% of the rate of that of ATP in the reverse biosynthetic reaction. If P1 is replaced by arsenate, the enzymatic rate of the AMP-supported hydrolysis of L-glutamine is 100-fold faster than is PPi synthesis and is one-half the rate of the ADP-supported, irreversible arsenolysis of L-glutamine. This latter activity also is supported by GMP and IMP, suggesting that the catalytic site of glutamine synthetase has a rather broad specificity for the nucleotide base. The reactions supported by AMP directly relate to the mechanism of glutamine synthetase catalysis.

Adenosine Monophosphate↗

PubMed1981

[Stable compound of inorganic pyrophosphatase with pyrophosphate obtained by a fluoride-mediated reaction with phosphate].

Incubation of inorganic pyrophosphate from baker's yeast with phosphate and MgCl2 in the presence of fluoride results in a gradual inactivation of the enzyme concomitant with incorporation of PP1 (about 2 moles per mole) into the protein. The rate constant for this process shows an increase with a rise in concentrations of the three reagents, the maximal value of inactivation being 0.11 min-1. The bound PP1 is not separated by gel-filtration. The rate of spontaneous degradation of the enzyme-pyrophosphate complex and the nature of EDTA and Mg2+ effects are similar to those for the analogous compound obtained by inhibition of PP1 hydrolysis by fluoride. The data obtained suggest that during PP1 synthesis and hydrolysis by pyrophosphatase fluoride stabilizes the same intermediate of the enzyme with pyrophosphate.

Diphosphates↗

PubMed1982

Isoleucyl-tRNA synthetase from Escherichia coli MRE 600. Different pathways of the aminoacylation reaction depending on presence of pyrophosphatase, order of substrate addition in the pyrophosphate exchange, and substrate specificity with regard to ATP analogs.

The substrate specificity of isoleucyl-tRNA synthetase from Escherichia coli MRE 600 with regard to ATP analogs has been compared with the results obtained with isoleucyl-tRNA synthetase from yeast. The enzyme from E. coli is less specific, the two enzymes exhibit different topographies of their active centres. The order of substrate addition to isoleucyl-tRNA synthetase from E. coli MRE 600 has been investigated by bisubstrate kinetics, product inhibition and inhibition by substrate analogs. The inhibition studies were done in the aminoacylation and in the pyrophosphate exchange reaction, the aminoacylation was investigated in the absence and presence of inorganic pyrophosphatase. As found for isoleucyl-tRNA synthetase from yeast, the results of the pyrophosphate exchange studies indicate the possibility of formation of E . Ile-AMP . ATP complexes by random addition of one ATP and one isoleucine molecule, followed by adenylate formation, release of pyrophosphate and subsequent addition of a second molecule of ATP. For the aminoacylation in the absence of pyrophosphatase, a rapid-equilibrium random ter addition of the substrates is found whereas the enzyme from yeast exhibits a steady-state ordered ter-ter mechanism; in the presence of pyrophosphatase the mechanism is bi-uni uni-bi ping-pong similarly as observed for the yeast enzyme. A comparison of inhibition patterns obtained with N(6)-benzyladenosine 5'-triphosphate under different assay conditions (spermine or magnesium ions, addition of pyrophosphatase) indicates that even more than two pathways of the aminoacylation may exist. The catalytic cycles of the two mechanisms derived from the observed orders of substrate addition and product release include the same enzyme substrate complex (E . tRNA . Ile-AMP) for the aminoacyl transfer reaction. The kcat values, however, are considerably different: kcat of the sequential pathway is about 40% lower than kcat of the ping-pong mechanism.

Adenosine Triphosphate↗