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 1,099 records · Page 61Linked to original sources
PubMed1999

Inorganic polyphosphate: a molecule of many functions.

Pursuit of the enzymes that make and degrade polyP has provided analytic reagents which confirm the ubiquity of polyP in microbes and animals and provide reliable means for measuring very low concentrations. Many distinctive functions appear likely for polyP depending on its abundance, chain length, biologic source and subcellular location: an energy supply and ATP substitute, a reservoir for Pi, a chelator of metals, a buffer against alkali, a channel for DNA entry, a cell capsule, and, of major interest, a regulator of responses to stresses and adjustments for survival in the stationary phase of culture growth and development. Whether microbe or human, we depend on adaptations in the stationary phase, a dynamic phase of life. Much attention has focused on the early and reproductive phases of organisms, rather brief intervals of rapid growth, but more concern needs to be given to the extensive period of maturity. Survival of microbial species depends on being able to manage in the stationary phase. In view of the universality and complexity of basic biochemical mechanisms, it would be surprising if some of the variety of polyP functions observed in microorganisms did not apply to aspects of human growth and development, to aging and to the aberrations of disease. Of theoretical interest regarding polyP is its antiquity in prebiotic evolution, which, along with its high energy and phosphate content, make it a plausible precursor to RNA, DNA and proteins. Of practical interest is its many industrial applications, among which is its use in the microbial depollution of Pi in marine environments.

Amino Acid Sequence↗
PubMed1979

The stimulation of Escherichia coli stringent factor-dependent synthesis of guanosine 3',5'-polyphosphate [(p)ppGpp] by rat liver ribosomal proteins.

The effect of groups of proteins from rat liver ribosomes on the Escherichia coli stringent factor-catalyzed synthesis of (p)ppGpp was tested. Most groups were capable of supporting (p)ppGpp synthesis; the exceptions were A40, B140, B240 and B160 which contain proteins which are relatively less basic than those in the active groups. The capacity of 30 individual rat liver ribosomal proteins to activate stringent factor was assessed; most sustained the synthesis of (p)ppGpp. Proteins S12, S21, L12, P1, and P2 (which are acidic or relatively acid) had no activity; proteins S6, S8, and L3 were the most active: the others had moderate activity.

Animals↗
PubMed1978

Effect of guanosine 5'-diphosphate 3'-diphosphate and related nucleoside polyphosphates on induction of tryptophanase and beta-galactosidase in permeabilized cells of Escherichia coli.

Exogenous addition of guanosine and adenosine 5'-(mono, di and tri) phosphate 3'-diphosphates (pppGpp, ppGpp, pGpp, pppApp, ppApp and pApp) stimulated the synthesis of tryptophanase and beta-galactosidase in permeabilized cells of Escherichia coli. From the results obtained with ppGpp and pppApp, this effect appeared to be at a transcriptional level and depended greatly on the growth condition; the largest effect was observed in cells under shiftdown or grown on poor enrgy source. ppGpp and pppApp, unlike cyclic AMP, did not act to overcome the inhibition of enzyme induction by glucose, but in combination with cyclic AMP caused a synergistic stimulation effect. In the shiftdown cells, ppGpp and pppApp gave 30% or more stimulation effect on tryptophanase induction while cyclic AMP did not stimulate induction. There was therefore a pronounced difference between cyclic AMP and ppGpp or pppApp in stimulatory function.

Adenine Nucleotides↗
PubMed1980

Effect of adenosine-5'-triphosphate-3'-diphosphate and related nucleoside polyphosphates on the spore germination of Streptomyces galilaeus.

Exogenous addition of adenosine- and guanosine 5'-(di- and tri) phosphate 3'-diphosphate (pppApp, ppApp, pppGpp and ppGpp) at the concentration of 0.5 mM inhibits spore germination of Streptomyces galilaeus ATCC 31133. This reversible inhibitory effect appeared to be at the transcriptional level, and also depends on the phase of spore germination; pppApp inhibited more strongly RNA synthesis in the period of the germ tube emergence than the early stage of germination. No inhibitory effect was observed with normal purine and pyrimidine nucleosides, nucleotides, pApp, pGpp, cyclic AMP and pyrophosphoric acid at the concentration of 0.1 - 1.0 mM.

Adenine Nucleotides↗
PubMed1990

Adsorption of 5'-adenosine monophosphate onto precipitated calcium phosphate: effects of inorganic polyphosphates and carbamyl phosphate.

In this paper it is shown that the adsorption of 5'-adenosine monophosphate (5'-AMP) onto precipitated calcium phosphate exhibits a sigmoidal profile as revealed by isotherms at 45 degrees C. This result indicates a cooperative behavior in the adsorption of 5'-AMP. The relationship between adsorption capacity and surface area of the sedimented matrix may be interpreted as an indication that there is a monolayer of the absorbed nucleotide on the solid surface. The pH dependence of adsorption suggests that the negatively charged phosphoryl group of 5'-AMP interacts with a positively charged site (possibly Ca2+) on the matrix surface. The adsorption of the nucleotide is markedly decreased at pH values above 8.0. The Dixon-like plot of the effect of pH suggests an inhibitory role of hydroxyl ions in the adsorption of 5'-AMP. At pH 7.5, other anions such as pyrophosphate, tripolyphosphate and carbamyl phosphate also inhibit the adsorption of the nucleotide, probably by interacting with its adsorption site. We suggest that these phosphorylated molecules could have played a role in chemical evolution by modulating the amount of nucleotides adsorbed onto mineral surfaces. The significance of these phenomena in chemical evolution is discussed.

Adenosine Monophosphate↗