Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Polyphosphates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1996

Genetic manipulation of polyphosphate metabolism affects cadmium tolerance in Escherichia coli.

The polyphosphate metabolic pathways in Escherichia coli were genetically manipulated to test the effect of polyphosphate on tolerance to cadmium. A polyphosphate kinase (ppk) and polyphosphatase (ppx) mutant strain produced no polyphosphate, whereas the same strain carrying multiple copies of ppk on a high-copy plasmid produced significant quantities. The doubling times of both strains increased with increasing cadmium concentrations. In contrast, the mutant strain carrying multiple copies of ppk and ppx produced 1/20 of the polyphosphate found in the strain carrying multiple copies of ppk only and showed no significant increase in doubling time over the same cadmium concentration range.

Acid Anhydride Hydrolases↗
PubMed2000

Atypical polyphosphate accumulation by the denitrifying bacterium Paracoccus denitrificans.

Polyphosphate accumulation by Paracoccus denitrificans was examined under aerobic, anoxic, and anaerobic conditions. Polyphosphate synthesis by this denitrifier took place with either oxygen or nitrate as the electron acceptor and in the presence of an external carbon source. Cells were capable of poly-beta-hydroxybutyrate (PHB) synthesis, but no polyphosphate was produced when PHB-rich cells were incubated under anoxic conditions in the absence of an external carbon source. By comparison of these findings to those with polyphosphate-accumulating organisms thought to be responsible for phosphate removal in activated sludge systems, it is concluded that P. denitrificans is capable of combined phosphate and nitrate removal without the need for alternating anaerobic/aerobic or anaerobic/anoxic switches. Studies on additional denitrifying isolates from a denitrifying fluidized bed reactor suggested that polyphosphate accumulation is widespread among denitrifiers.

Acetates↗
PubMed1988

Utilization by Escherichia coli of a high-molecular-weight, linear polyphosphate: roles of phosphatases and pore proteins.

We observed that wild-type Escherichia coli utilized a linear polyphosphate with a chain length of 100 phosphate residues (poly-P100) as the sole source of phosphate in growth medium. A mutation in the gene phoA of alkaline phosphatase or phoB, the positive regulatory gene, prevented growth in this medium. Since no alkaline phosphatase activity was detected outside the wild-type cells, the periplasmic presence of the enzyme was necessary for the degradation of polyphosphate. A 90% reduction in the activity of periplasmic acid phosphatase with a pH optimum of 2.5 (delta appA mutants) did not affect polyphosphate utilization. Of the porins analyzed (OmpC, OmpF, and PhoE), the phoB-inducible porin PhoE was not essential since its absence did not prevent growth. To study how poly-P100 diffused into the cells, we used high-resolution 31P nuclear magnetic resonance (31P NMR) spectroscopy. The results suggest that poly-P100 entered the periplasm and remained in equilibrium between the periplasm and the medium. When present individually, porins PhoE and OmpF facilitated a higher permeability for poly-P100 than porin OmpC did. The degradation of polyphosphate by intact cells of E. coli observed by 31P NMR showed a time-dependent increase in cellular phosphate and a decrease in polyphosphate concentration.

Alkaline Phosphatase↗
PubMedDate not supplied

[Inactivation of the ppn1 gene exerts different effects on the metabolism of inorganic polyphosphates in the cytosol and the vacuoles of the yeast Saccharomyces cerevisiae].

Inactivation of the PPN1 gene, encoding one of the enzymes involved in polyphosphate metabolism in the yeast Saccharomyces cerevisiae, was found to decrease exopolyphosphatase activity in the cytosol and vacuoles. This effect was more pronounced in the stationary growth phase than in the phase of active growth. The gene inactivation resulted in elimination of a approximately 440-kDa exopolyphosphatase in the vacuoles but did not influence a previously unknown vacuolar exopolyphosphatase with a molecular mass of >1000 kDa, which differed from the former enzyme in the requirement for bivalent cations and sensitivity to heparin. Inactivation of the PPN1 gene did not influence the level of polyphosphates in the cytosol but increased it more than twofold in the vacuoles. In this case, the polyphosphate chain length in the cytosol increased from 10-15 to 130 phosphate residues both in the stationary and active growth phases. In the vacuoles, the polyphosphate length increased only in the stationary growth phase. A conclusion can be made that the PPN1 gene product has different effects on polyphosphate metabolism in the cytosol and the vacuoles.

Acid Anhydride Hydrolases↗
PubMed1980

[Localization of polyphosphates in cells of microorganisms using 31-P-NMR-145, 75 MHz of high resolution].

Using the method of 31P-NMR of high resolution at 145,78 MHz the presence of mobile inorganic polyphosphates in the cells of actinomycetes (Mycobacterium smegmatis), yeasts (Candida albicans and Endomyces magnusii) and bacteria (E. coli) was established. A considerable increase in the intensity and a low field shift of the polyphosphate signal after addition of EDTA to the M. Smegmatis cells can be indicative of possible localization of inorganic polyphosphates in the periplasmic space. The lack of effect of exogenous EDTA and Mn2+ on the polyphosphate signal in the spectrum of E. magnusii cells is probably due to localization of polyphosphates inside the cells. A comparison of 31P-NMR spectra of living cells and bacterial extracts of Staphylococcus aureus, Micrococcus lysodeikticus, Bacillus antracoides, B. megaterium and Salmonella typhimurium is given.

Ascomycota↗
PubMed1982

[Polyphosphate and ATP content of Propionibacterium shermanii cells in nitrogen starvation].

When Propionibacterium shermanii was cultivated in a medium with glucose under the conditions of nitrogen deficiency, the content of high molecular weight polyphosphates (salt-soluble fraction, alkali-soluble fraction, and fraction extracted with hot perchloric acid) decreased. In contrast, it rose in a medium with lactate within two and three days of starvation. The culture growth stopped after a day under these conditions, the energy substrate was assimilated during the entire process of starvation, and the content of ATP continuously decreased. When ammonium sulfate was added after two and three days of starvation, the intracellular content of polyphosphates (in all of the three fractions) increased in the medium with glucose. If ammonium sulfate was added after three days of starvation in the medium with lactate, the content of polyphosphates rose in the fraction extracted with hot perchloric acid while the content of salt-soluble and alkali-soluble polyphosphates decreased. The culture started to grow again and the content of ATP in its cells rose abruptly when ammonium sulfate was added under these conditions. If the culture was grown in the medium with glucose and ammonium sulfate, the content of acid-insoluble polyphosphates increased twofold during the first day and dropped to the initial level by the third day of growth.

Adenosine Triphosphate↗
PubMedDate not supplied

[Hypochromic effect of signal attenuation in 31P-NMR spectra of linear polyphosphates].

Chemical shifts in 31P-NMR spectra of linear polyphosphates were studied. In each polyphosphate species tested, the sum of signal intensities of the internal (core) phosphate groups was proportional to the concentration of each polyphosphate, but the contribution of such groups to the total intensity of the signal decreased with increasing the length of the polyphosphate chain. An equation for estimating the polyphosphate chain length in biological objects taking into account a decrease in the 31P-NMR spectral intensity is proposed.

Nuclear Magnetic Resonance, Biomolecular↗
PubMed2002

Coexistence of liquid phases in the sodium polyphosphate-chromium nitrate-water system.

The formation of coexisting liquid phases out of aqueous aluminum polyphosphate solutions was previously suggested as an essential step in aluminum polyphosphate nanoparticle formation. This hypothesis could not be directly verified because the separation of the two phases is very difficult, but a different situation was found in the case of chromium (III) polyphosphate. The phase diagram of the sodium polyphosphate-chromium nitrate-water system at 25 degrees C presents an extensive region with two coexisting liquid phases (L-L), together with a single liquid phase (L) and a solid-liquid (S-L) domain. Within the L-L region, admixture of the reagents produces initially a turbid liquid, out of which two transparent liquid phases separate in a short time, under gravity: one is dense, dark, and viscous while the other has a light color and a lower density. The amounts of the separated phases were determined, as well as their viscosities, densities, pH, UV-vis spectra, and relevant molalities: P (from polyphosphate), Cr(3+), NO(-)(3+), and Na(+). The two liquid phases undergo significant color, pH, and viscosity changes with time. The calculated phase diagrams display the major features of the experimental phase diagram.

Journal Article↗
PubMed1994

Crystallization and initial X-ray crystallographic characterization of recombinant bovine inositol polyphosphate 1-phosphatase produced in Spodoptera frugiperda cells.

Bovine inositol polyphosphate 1-phosphatase, a monomeric protein with a molecular mass of 44,000 Da, hydrolyzes the 1-position phosphate from inositol 1,3,4-trisphosphate and inositol 1,4-bisphosphate. The low abundance of inositol polyphosphate 1-phosphatase in tissues has precluded structural studies requiring large quantities of enzyme. We used recombinant Baculovirus harboring the cDNA of bovine inositol polyphosphate 1-phosphatase to infect Spodoptera frugiperda (Sf9) insect cells. Recombinant protein (25 mg per 1 x 10(9) cells) was purified to homogeneity. The enzyme produced in Sf9 cells was similar to the native purified protein as determined by immunoblotting catalytic properties, and inhibition by lithium ions. Crystals of the purified recombinant enzyme were grown by vapor diffusion. Precession photography was used to determine the parameters of inositol polyphosphate 1-phosphatase crystals. The tetragonal crystals belong to the space group P4(1) or P4(3), have unit cell dimensions of a = b = 51.6 A, c = 143.3 A, alpha = beta = gamma = 90 degrees, and contain one molecule per asymmetric unit. We have collected a complete diffraction data set extending to 2.3 A and are currently attempting to solve the three-dimensional structure of bovine inositol polyphosphate 1-phosphatase using a multiple isomorphous replacement strategy.

Animals↗
PubMed1995

P2 purinergic receptors for diadenosine polyphosphates in the nervous system.

1. The actions of diadenosine polyphosphates, diadenosine tetraphosphate (Ap4A), diadenosine pentaphosphate (Ap5A) and diadenosine hexaphosphate (Ap6A) in the nervous system have been reviewed. 2. In the peripheral nervous system, diadenosine polyphosphates bind to P2-purinergic receptors such as the P2Y in chromaffin cells and Torpedo synaptosomes, P2X in vas deferens and urinary bladder and also Torpedo synaptosomes and P2U in endothelial chromaffin cells. 3. In the central nervous system ApnA compounds can act through P2X-purinoceptors opening cation channels in nodose ganglion neurones. Diadenosine polyphosphates bind to a P2d-purinergic receptor in rat brain synaptic terminals and hippocampus, linked to protein kinase C (PKC) activation. 4. P4-purinoceptors are specific receptors for diadenosine polyphosphates, coupled to the Ca2+ influx, in the central synapses. This purinoceptor is not activated by ATP and synthetic analogs. The P4-purinoceptor could act as a positive modulator of the synaptic transmission, giving even more importance to diadenosine polyphosphates as neurotransmitters.

Animals↗
PubMed2000

Diadenosine polyphosphates facilitate the evoked release of acetylcholine from rat hippocampal nerve terminals.

Diadenosine polyphosphates are present in synaptic vesicles, are released upon nerve stimulation and possess membrane receptors, namely in presynaptic terminals. However, the role of diadenosine polyphosphates to control neurotransmitter release in the CNS is not known. We now show that diadenosine pentaphosphate (Ap(5)A, 3-100 microM) facilitated in a concentration dependent manner the evoked release of acetylcholine from hippocampal nerve terminals, with a maximal facilitatory effect of 116% obtained with 30 microM Ap(5)A. The selective diadenosine polyphosphate receptor antagonist, diinosine pentaphosphate (Ip(5)I, 1 microM), inhibited by 75% the facilitatory effect of Ap(5)A (30 microM), whereas the P(2) receptor antagonists, suramin (100 microM) and pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS, 10 microM) only caused a 18-24% inhibition, the adenosine A(1) receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (20 nM), caused a 36% inhibition and the adenosine A(2A) receptor antagonist, 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo [2,3-a][1,3, 5]triazin-5-ylamino]ethyl)phenol (ZM 241385, 20 nM), was devoid of effect. These results show that diadenosine polyphosphates act as neuromodulators in the CNS, facilitating the evoked release of acetylcholine mainly through activation of diadenosine polyphosphate receptors.

Acetylcholine↗
PubMed1998

Purification of chemically synthesised dinucleoside(5',5') polyphosphates by displacement chromatography.

Dinucleoside(5',5') polyphosphates (ApnA, ApnG, GpnG, n=3-6) are new group of hormones controlling important biological processes. Because some of the dinucleoside(5',5') polyphosphates are commercially not available purification of chemical synthesised dinucleoside(5',5') polyphosphates became necessary in order to test their physiological and pharmacological properties. It was the aim of this study to find a method which allows purification of 0.1-0.2 g quantities of dinucleoside polyphosphates by analytical HPLC columns yielding products with impurities lower than 1.0%. Adenosine(5')-polyphospho-(5')guanosines were synthesised by mixing the corresponding mononucleotides. The reaction results in a complex mixture of ApnA, ApnG and GpnG (with n=3-6 in all cases). The reaction mixture was concentrated on a preparative C18 reversed-phase column. The concentrate was displaced on a reversed-phase stationary. As a result of displacement chromatography, anion-exchange chromatography in gradient modus yielded baseline separated dinucleoside polyphosphates (homogeneity of the fractions>99%). The identity of the substances were determined by matrix assisted laser desorption ionisation mass spectrometry.

Chromatography, High Pressure Liquid↗
PubMed2000

Characterization of polyphosphates by electrospray mass spectrometry

Electrospray ionization mass spectrometry (ESI-MS) was applied for the characterization of inorganic polyphosphates [orthophosphate, pyrophosphate, tripolyphosphate, trimetaphosphate, and tetrapolyphosphatel. The high selectivity of ESI-MS allows the detection of different polyphosphate species without preseparation by ion chromatography or capillary electrophoresis. Furthermore, ESI-MS does not require the incorporation of UV-absorbing chromophores into the analytical method for the detection of phosphates, unlike conventional UV-chromatographic methods. Limits of detection by ESI-MS were estimated to range from approximately 1 to 10 ng/mL. The quantification of polyphosphate samples as single-component and multicomponent mixtures was investigated. Linear signal response for single-component samples ranged from the limit of detection to approximately 10 microg/mL Quantification of polyphosphate in streamwater is demonstrated using the standard addition method. The effect of multi-polyphosphate components and salts on signal response was also studied. For concentrations less than 2.0 microg/mL, signal response from a tetrapolyphosphate sample was comparable to those obtained from tetrapolyphosphate-tripolyphosphate mixtures. Signal response obtained from tetrapolyphosphate in the presence of tripolyphosphate or NH4NO3 at higher concentrations (approximately 50 microg/mL and 35 microg/mL, respectively) was significantly lower relative to single-component standards (approximately 40%-70%).

Journal Article↗
PubMed1997

Polyphosphate kinase is a component of the Escherichia coli RNA degradosome.

The Escherichia coli degradosome is a multienzyme complex with four major protein components: the endoribonuclease RNase E, the exoribonuclease PNPase, the RNA helicase RhlB and enolase. The first three of these proteins are known to have important functions in mRNA processing and degradation. In this work, we identify an additional component of the degradosome, polyphosphate kinase (PPK), which catalyses the reversible polymerization of the gamma-phosphate of ATP into polyphosphate (poly(P)). An E. coli strain deleted for the ppk gene showed increased stability of the ompA mRNA. Purified His-tagged PPK was shown to bind RNA, and RNA binding was prevented by hydrolysable ATP. Chemical modification of RNA by PPK, for example the addition or removal of 3' or 5' terminal phosphates, could not be detected. However, polyphosphate was found to inhibit RNA degradation by the degradosome in vitro. This inhibition was overcome by the addition of ADP, required for the degradation of polyphosphate and for the regeneration of ATP by PPK in the degradosome. Thus, PPK in the degradosome appears to maintain an appropriate microenvironment, removing inhibitory polyphosphate and NDPs and regenerating ATP.

Adenosine Triphosphate↗
PubMed2005

An essential role for an inositol polyphosphate multikinase, Ipk2, in mouse embryogenesis and second messenger production.

Phospholipase C and several inositol polyphosphate kinase (IPK) activities generate a branched ensemble of inositol polyphosphate second messengers that regulate cellular signaling pathways in the nucleus and cytoplasm. Here, we report that mice deficient for Ipk2 (also known as inositol polyphosphate multikinase), an inositol trisphosphate and tetrakisphosphate 6/5/3-kinase active at several places in the inositol metabolic pathways, die around embryonic day 9.5 with multiple morphological defects, including abnormal folding of the neural tube. Metabolic analysis of Ipk2-deficient cells demonstrates that synthesis of the majority of inositol pentakisphosphate, hexakisphosphate and pyrophosphate species are disrupted, although the presence of 10% residual inositol hexakisphosphate indicates the existence of a minor alternative pathway. Agonist induced inositol tris- and bis-phosphate production and calcium release responses are present in homozygous mutant cells, indicating that the observed mouse phenotypes are a result of failure to produce higher inositol polyphosphates. Our data demonstrate that Ipk2 plays a major role in the synthesis of inositol polyphosphate messengers derived from inositol 1,4,5-trisphosphate and uncovers a role for their production in embryogenesis and normal development.

Animals↗
PubMed1993

Cloning, heterologous expression, and chromosomal localization of human inositol polyphosphate 1-phosphatase.

Inositol polyphosphate 1-phosphatase, an enzyme in the phosphatidylinositol signaling pathway, catalyzes the hydrolysis of the 1 position phosphate from inositol 1,3,4-trisphosphate and inositol 1,4-bisphosphate. We used a cDNA that encodes bovine inositol polyphosphate 1-phosphatase as a probe to isolate the human counterpart by low-stringency hybridization. The 1.74-kb human cDNA has 341 bp of 5' untranslated region, 180 bp of 3' untranslated region, poly(A)32, and predicts a protein of 399 amino acids. Human and bovine inositol polyphosphate 1-phosphatases show 84% amino acid sequence identity. Northern blot analysis from a variety of human tissues demonstrates that a 1.9-kb mRNA is ubiquitously expressed with highest levels in pancreas and kidney. Several higher molecular weight mRNAs also are expressed in brain, muscle, heart, and liver. We have confirmed the functional identity of the human cDNA by heterologous expression in NIH 3T3 fibroblasts, COS-7 cells and Escherichia coli. Polymerase chain reaction assay of a panel of human-rodent somatic cell hybrid DNA using human inositol polyphosphate 1-phosphatase-specific DNA primers resulted in amplification of a specific product using chromosome 2 DNA as template. Fluorescence in situ hybridization of metaphase chromosomes localizes the gene to chromosome 2 band q32. The identification of the human inositol polyphosphate 1-phosphatase gene locus provides a target for linkage analysis to identify defects in patients with inherited psychiatric disorders that respond to lithium ions, an inhibitor of the enzyme.

3T3 Cells↗
PubMed1995

An alleged yeast polyphosphate kinase is actually diadenosine-5', 5"'-P1,P4-tetraphosphate alpha,beta-phosphorylase.

Polyphosphates are a major constituent of the yeast Saccharomyces cerevisiae. A purification of the enzyme polyphosphate kinase (E.C. 2.7.4.1) from this organism has been reported (Felter, S., and Stahl, A.J.C. (1973) Biochimie (Paris) 55, 245-251). The assay for activity used in this purification was the production of 32P-labeled nucleotide, presumed to be ATP, in the presence of [32P]polyphosphate and ADP. We have found that this assay does not reflect the activity of a polyphosphate kinase but rather the combination of an exopolyphosphatase, releasing free [32P]phosphate from the added [32P]polyphosphate, and the ADP-[32P]phosphate exchange activity of the enzyme diadenosine 5',5"'-P1, P4-tetraphosphate alpha, beta-phosphorylase (Ap4A phosphorylase). We also present direct evidence for the formation of an enzyme-AMP intermediate in the actin of Ap4A phosphorylase.

Adenosine Monophosphate↗
PubMed2002

In Saccharomyces cerevisiae, the inositol polyphosphate kinase activity of Kcs1p is required for resistance to salt stress, cell wall integrity, and vacuolar morphogenesis.

A problem for inositol signaling is to understand the significance of the kinases that convert inositol hexakisphosphate to diphosphoinositol polyphosphates. This kinase activity is catalyzed by Kcs1p in the yeast Saccharomyces cerevisiae. A kcs1Delta yeast strain that was transformed with a specifically "kinase-dead" kcs1p mutant did not synthesize diphosphoinositol polyphosphates, and the cells contained a fragmented vacuolar compartment. Biogenesis of the yeast vacuole also required another functional domain in Kcs1p, which contains two leucine heptad repeats. The kinase activity of Kcs1p was also found to sustain cell growth and integrity of the cell wall and to promote adaptive responses to salt stress. Thus, the synthesis of diphosphoinositol polyphosphates has wide ranging physiological significance. Furthermore, we showed that these phenotypic responses to Kcs1p deletion also arise when synthesis of precursor material for the diphosphoinositol polyphosphates is blocked in arg82Delta cells. This metabolic block was partially bypassed, and the phenotype was partially rescued, when Kcs1p was overexpressed in the arg82Delta cells. This was due, in part, to the ability of Kcs1p to phosphorylate a wider range of substrates than previously appreciated. Our results show that diphosphoinositol polyphosphate synthase activity is essential for biogenesis of the yeast vacuole and the cell's responses to certain environmental stresses.

Cell Wall↗