Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When inorganic phosphate is limiting, Arabidopsis has the facultative ability to metabolize exogenous nucleic acid substrates, which we utilized previously to identify insensitive phosphate starvation response mutants in a conditional genetic screen. In this study, we examined the effect of the phosphate analog, phosphite (Phi), on molecular and morphological responses to phosphate starvation. Phi significantly inhibited plant growth on phosphate-sufficient (2 mM) and nucleic acid-containing (2 mM phosphorus) media at concentrations higher than 2.5 mM. However, with respect to suppressing typical responses to phosphate limitation, Phi effects were very similar to those of phosphate. Phosphate starvation responses, which we examined and found to be almost identically affected by both anions, included changes in: (a) the root-to-shoot ratio; (b) root hair formation; (c) anthocyanin accumulation; (d) the activities of phosphate starvation-inducible nucleolytic enzymes, including ribonuclease, phosphodiesterase, and acid phosphatase; and (e) steady-state mRNA levels of phosphate starvation-inducible genes. It is important that induction of primary auxin response genes by indole-3-acetic acid in the presence of growth-inhibitory Phi concentrations suggests that Phi selectively inhibits phosphate starvation responses. Thus, the use of Phi may allow further dissection of phosphate signaling by genetic selection for constitutive phosphate starvation response mutants on media containing organophosphates as the only source of phosphorus.
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PMID:Attenuation of phosphate starvation responses by phosphite in Arabidopsis. 1170 78

Different pleiotropic transcriptional regulators are known to function in the coordination of regulons concerned with carbon, nitrogen, sulfur, phosphorus and iron metabolism, but how expression profiles of these different regulons are coordinated with each other is not known. The basis for the effects of cysB mutations on carbon utilization in Escherichia coli and Salmonella typhimurium was examined. cysB mutations affected the utilization of some carbon sources more than others and these effects could be partially, but not completely, reversed by the inclusion of cysteine or djenkolate in the growth medium. Assays of transport systems and enzymes concerned with glucitol and alanine utilization showed that these activities were depressed in cysB mutants relative to isogenic wild-type strains, and cysteine or djenkolate present in the growth media partially restored these activities. Using transcriptional fusions to the fdo (formate dehydrogenase) and gut (glucitol) operons, it was shown that decreased expression resulted from defects at the transcriptional level. Furthermore, the effects of loss of CysB were much less pronounced under conditions of catabolite repression than in the absence of a catabolite-repressing carbon source, and cAMP largely reversed the effect of the loss of CysB. Comparable effects were seen for E. coli lacZ gene expression under the control of its own native promoter, and sulfur limitation in a cysB mutant depressed net cAMP production in a cAMP phosphodiesterase mutant. Adenylate cyclase thus appears to be responsive to sulfur deprivation. These observations may have physiological significance allowing carbon and sulfur regulon coordination during the growth of enteric bacteria in response to nutrient availability.
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PMID:Regulation of carbon utilization by sulfur availability in Escherichia coli and Salmonella typhimurium. 1178 5

Activities of phytase, a pH 6.0 optimum nonspecific phosphomonoesterase and phosphodiesterase assayed toward bis(p-nitrophenyl)phosphate (phosphodiesterase I) and against p-nitrophenylphosphorylcholine (phosphodiesterase II), were partially purified from mycelial extracts of Aspergillus niger AbZ4 cultivated on a molasses medium by a liquid surface fermentation method. After elimination of phosphate from the medium, 7.3- and 3.5-fold enhancements in specific activities of phytase and phosphodiesterase II were observed. Efficacies of mycelial protein fractions in dephosphorylating a wheat-based broiler feed were determined in vitro according to a procedure that simulated digestion in the intestinal tract of poultry. The addition of 0.052 mg of protein from fractions, each of which was high in either pH 6.0 optimum phosphomonoesterase, phosphodiesterase I, phosphodiesterase II, or phytase per gram of a feed sample resulted in the enhancement of phosphorus release by 10, 11, 27, and 88%, respectively. In the presence of an excess of commercial phytase, the addition of the mycelial fraction high in phytase increased the dephosphorylation rate by 56%. The fraction high in phosphodiesterase II enhanced feed dephosphorylation by 8% in the presence of an excess of commercial phytase and commercial acid phosphatase.
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PMID:In vitro efficacies of phosphorolytic enzymes synthesized in mycelial cells of Aspergillus niger AbZ4 grown by a liquid surface fermentation. 1182 65

Extracellular adenosine triphosphate (ATP) regulates platelet reactivity by way of direct action on platelet purinergic receptors or by hydrolysis to adenosine diphosphate (ADP). Subsequent metabolism of ATP and ADP to adenosine monophosphate (AMP) and adenosine inhibits platelet aggregation. Endothelial cell membrane-bound ecto-ATP/ADPase (CD39, E-NTPDase1) is thought to be the main regulator of platelet responsiveness. However, the findings in studies of CD39-knockout mice imply that nucleotidase(s) in plasma regulates circulating adenine nucleotides levels. Understanding extracellular ATP metabolism by CD39 and plasma nucleotidases is therefore important. In this study, alpha-phosphorus 32- and gamma-phosphorus 32-labeled ATP were rapidly metabolized directly to AMP and pyrophosphate in human plasma at pH 7.4, suggesting the presence of pyrophosphatase/phosphodiesterase-like activity. A specific phosphodiesterase substrate, p-nitrophenol-5'-TMP (p-Nph-5'-TMP), was readily hydrolyzed in human plasma. The antiaggregatory action of beta,gamma-methylene-ATP (AMPPCP) (5 micromol/L) was blocked by DMPX, an adenosine-receptor antagonist, suggesting that in plasma, AMPPCP was metabolized to AMP and adenosine. Recombinant soluble CD39 (solCD39) was used to assess the role of CD39 in ATP metabolism. As little as 0.25 microg/mL of solCD39 inhibited ADP-induced platelet aggregation. However, in the presence of ADP-free ATP (10 micromol/L), solCD39 induced platelet aggregation in a dose-dependent manner. Because AMPPCP could not substitute for ATP in solCD39-stimulated platelet aggregation, it is likely that ADP formation from ATP was required. Endogenous CD39 may thus have a hemostatic function by promoting ADP formation from released ATP, in addition to its antiaggregatory properties. A plasma nucleotidase hydrolyzes ATP directly to AMP. This prevents ADP accumulation and generates adenosine, a potent, locally acting inhibitor of platelet reactivity. The presence of both endothelial CD39 and plasma nucleotidase appears to be important in the maintenance of normal hemostasis and prevention of excessive platelet responsiveness.
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PMID:Role of extracellular ATP metabolism in regulation of platelet reactivity. 1227 Dec 74

Enzymatic hydrolysis and mineralization of organic phosphorus (P) were determined in surface water samples collected from inflow and outflow of a submerged aquatic vegetation (SAV)-dominated treatment wetland of the Florida Everglades. Water samples were fractionated into three size fractions (> 0.4 micron, < 0.4 to > 0.05 micron, and < 0.05 micron) with a sequential flow filtration technique. The fractionated water samples were incubated to hydrolyze with alkaline phosphatase (APase) and phosphodiesterase (PDEase), and to mineralize at different redox and pH. Unlike APase, which hydrolyzed < or = 10% of organic P, PDEase hydrolyzed > or = 71% of organic P in unfiltered water from both inflow and outflow waters, suggesting the domination of bioavailable diester P in the water. Phosphodiesterase completely hydrolyzed organic P in the < 0.4- to > 0.05-micron and < 0.05-micron fractions, as compared with < or = 35% in the > 0.4-micron fraction. However, the P mineralization in inflow and outflow waters at different redox and pH showed that P associated with particulate > 0.4 micron had been mineralized the most. Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy showed that surficial sediments from the inflow region contained a high proportion of polynucleotides, nucleoside monophosphates, and previously unreported glycerophosphoethanolamine and phosphoenolpyruvates. However, at the outflow, the relative proportion of polynucleotides and nucleoside monophosphates was reduced substantially. This suggests that the SAV wetland may sequester P via accretion of organic matter.
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PMID:Bioavailability of organic phosphorus in a submerged aquatic vegetation-dominated treatment wetland. 1237 Nov 95

Even though fungal phosphatases are widely used to study ambient-regulated gene expression, little is known about these enzymes in the agriculturally important genus Colletotrichum. We have therefore identified several phosphatase activities in endophytic isolates of Colletotrichum musae grown under conditions of nutritional sufficiency or starvation for sources of phosphorus (P), nitrogen (N), carbon (C), and sulphur (S). These enzyme forms could be distinguished by substrate specificity, optimum pH, activation and inhibition by some substances, response to nutritional starvation, and pattern of migration in native gel electrophoresis. At least four individual phosphatase activities were identified under the growth conditions employed. A pH 5.0 acid phosphatase and an Mg(2+)-dependent pH 7.5 phosphodiesterase were expressed under all growth conditions at constant rates. Under conditions of P-starvation, derepression of a major pH 6.0-acid phosphatase was observed in cell-free extracts and the culture medium. A synthesis of alkaline phosphatase activities followed a more distinct pattern. Under conditions of nutritional sufficiency of P- or N-starvation, only a single intracellular enzyme form (optimum pH 10) was observed, which was resolved as a single electrophoretic activity band. However, in media lacking C or S sources additional alkaline phosphatase forms were derepressed with a concomitant increase in the overall enzyme activity level measured at pH 10. To our knowledge, this report represents the most detailed study of phosphatases in Colletotrichum and the first partial characterization of the phosphatase system in an endophytic fungus.
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PMID:Synthesis and secretion of phosphatases by endophytic isolates of Colletotrichum musae grown under conditions of nutritional starvation. 1250 5

The phosphate (P(i)) starvation stimulon of Corynebacterium glutamicum was characterized by global gene expression analysis by using DNA microarrays. Hierarchical cluster analysis of the genes showing altered expression 10 to 180 min after a shift from P(i)-sufficient to P(i)-limiting conditions led to identification of five groups comprising 92 genes. Four of these groups included genes which are not directly involved in P metabolism and changed expression presumably due to the reduced growth rate observed after the shift or to the exchange of medium. One group, however, comprised 25 genes, most of which are obviously related to phosphorus (P) uptake and metabolism and exhibited 4- to >30-fold-greater expression after the shift to P(i) limitation. Among these genes, the RNA levels of the pstSCAB (ABC-type P(i) uptake system), glpQ (glycerophosphoryldiester phosphodiesterase), ugpAEBC (ABC-type sn-glycerol 3-phosphate uptake system), phoH (unknown function), nucH (extracellular nuclease), and Cgl0328 (5'-nucleotidase or related esterase) genes were increased, and pstSCAB exhibited a faster response than the other genes. Transcriptional fusion analyses revealed that elevated expression of pstSCAB and ugpAEBC was primarily due to transcriptional regulation. Several genes also involved in P uptake and metabolism were not affected by P(i) starvation; these included the genes encoding a PitA-like P(i) uptake system and a putative Na(+)-dependent P(i) transporter and the genes involved in the metabolism of pyrophosphate and polyphosphate. In summary, a global, time-resolved picture of the response of C. glutamicum to P(i) starvation was obtained.
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PMID:The phosphate starvation stimulon of Corynebacterium glutamicum determined by DNA microarray analyses. 1286 61

It has been shown by the work presented in this paper that it is possible to dephosphorylate enzymically pepsin and pepsinogen with a variety of phosphatases. With the aid of a phosphodiesterase and the prostate phosphatase it has been established that the phosphorus in the two proteins is present as a diester and connects two sites of the peptide chain in a cyclic configuration. Removal of the phosphorus does not affect the proteolytic activity against hemoglobin or the synthetic substrate acetyl-L-phenylalanyl diiodotryosine, nor the pepsinogen pepsin transformation. However, an increase of the autodigestion of pepsin is observed.
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PMID:Enzymic dephosphorylation of pepsin and pepsinogen. 1349 15

Phosphatase enzymes regulate organic phosphorus (P) turnover in soil, but a clear understanding remains elusive. To investigate this, phosphomonoesterase and phosphodiesterase activities were determined by using para-nitrophenol (pNP) analogue substrates in a range of temperate pasture soils from England and Wales. Substrate-induced phosphatase activity ranged between 2.62 and 12.19 micromol pNP g-1 soil h-1 for phosphomonoesterase and between 0.25 and 2.24 micromol pNP g-1 soil h-1 for phosphodiesterase. Activities were correlated strongly with soil pH and labile organic P extracted in sodium bicarbonate, although the relationships differed markedly for the two enzymes. Acidic soils contained high phosphomonoesterase activity, low phosphodiesterase activity, and high concentrations of labile organic P, whereas the reverse was true in more neutral soils. As most of the organic P inputs to soil are phosphate diesters, it therefore seems likely that phosphodiesterase activity regulates labile organic P turnover in pasture soils. The low phosphodiesterase activity in acidic soils may be linked to the dominance of fungi or an effect of sorption on the enzyme. These results suggest that greater emphasis should be placed on understanding the role of phosphodiesterase activity in the cycling of soil organic P.
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PMID:Phosphatase activity in temperate pasture soils: Potential regulation of labile organic phosphorus turnover by phosphodiesterase activity. 1590 8

Productivity in P limited peatlands is regulated in part by the turnover of organic phosphates, which is influenced by the chemical nature of the compounds involved. We used solution 31P nuclear magnetic resonance (NMR) spectroscopy to quantify organic and inorganic phosphates in benthic floc (a mixture of plant detritus and algae) and underlying soil from sites along P gradients in hard water and soft water areas of the northern Florida Everglades, USA. Phosphorus-enriched sites were dominated by cattail (Typha spp.), while unenriched sites included sawgrass (Cladium jamaicense Crantz) ridges and open-water sloughs. Phosphorus extracted in a solution containing 0.25 M NaOH and 50 mM EDTA (ethylenediaminetetraacetate) included phosphate, phosphate monoesters, DNA, and pyrophosphate. Signals from phosphate monoesters were consistent with those from alkaline hydrolysis products of RNA and phospholipids formed during extraction and analysis, whereas phytic acid (myo-inositol hexakisphosphate), the most abundant organic phosphate in most soils, was not detected. Phosphorus composition was similar among sites, although neither DNA nor pyrophosphate were detected in extracts of benthic floc from a calcareous slough. DNA was a greater proportion of the P extracted from soil compared to benthic floc, while the opposite was true for pyrophosphate. Research on the cycling of organic phosphates in wetlands focuses conventionally on the turnover of phosphate monoesters, but our results suggest strongly that greater emphasis should be given to understanding the role of phosphate diesters and phosphodiesterase activity.
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PMID:Phosphorus cycling in wetland soils: the importance of phosphate diesters. 1615 Dec 43


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