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:3.1.4.3 (phospholipase C)
18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nonhydrolyzable GTP analogue GTP-gamma-S was capable of stimulating in vitro phosphorylation of polyphosphoinositides in isolated nuclei prepared from mouse erythroleukemia cells. On the contrary, GDP-beta-S was ineffective. The stimulation was not detectable when nuclei were prepared from erythroleukemia cells induced to differentiate by exposure to dimethyl sulfoxide. Both nuclear phosphomonoesterase and phospholipase C activities were not influenced by GTP-gamma-S. Our results point to the likelihood that nuclear phosphoinositide kinases might be regulated by a GTP-binding protein.
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PMID:Stimulation of nuclear polyphosphoinositide synthesis by GTP-gamma-S: a potential regulatory role for nuclear GTP-binding proteins. 857 28

To determine biochemical changes associated with early parasite development, Haemonchus contortus larvae were cultured in vitro to the fourth stage (L4). Infective larvae developed from third to fourth stage in 48-96 h. Metabolic activity increased following stimulus of infective stages by CO2 secretion/excretion of significant amounts of protein into cultures and larval feeding did not occur until larvae had molted to the fourth stage. Larval feeding, as monitored by the ability of larvae to ingest fluorescein-labeled albumin, correlated with molting to the fourth stage and only fourth stage larvae were observed to feed. Fourth stage larvae secreted/excreted several enzymes into culture media including a metalloprotease, an acid phosphohydrolase, a cathepsin C-like enzyme, a phospholipase C-like enzyme and an N-acetyl-beta-D-glucosaminidase. Excretory-secretory (ES) products produced by L4 had antigenic homologies with parasite products produced during the second molt and with proteins and glycoproteins extracted from third and fourth stage larvae. ES products were recognized by sera from sheep infected with H. contortus. The enzymes identified here serve as markers for maturation to the fourth larval stage as well as the initiation of feeding and are likely to be involved in extracorporeal digestion. Further, they might serve as potential targets for immune or chemical control of trichostrongyle infections.
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PMID:Characterization of excretory-secretory products from larval stages of Haemonchus contortus cultured in vitro. 868 75

Epidermal enzymes play an important role in the process of differentiation of keratinocytes. The present preliminary in vitro study was undertaken to observe if topical enzyme treatment influenced permeation of compounds across the skin. Due to the noted function and importance of phosphatidylcholine metabolism during maturation of the barrier lipids, the effects of topical application of the phosphatidylcholine dependent phospholipase C enzyme (not present in epidermis) on skin penetration of three model drugs, viz. benzoic acid, mannitol and testosterone, were studied. Similar studies were also carried out using epidermal enzymes like triacylglycerol hydrolase, acid phosphatase, and phospholipase A2 (present in epidermis). Pretreatment of skin with phospholipase C significantly enhanced permeation of benzoic acid, mannitol, and testosterone relative to untreated skin. Triacylglycerol hydrolase (neutral) increased the penetration of mannitol 3-fold and had no effect on benzoic acid penetration. Topical application of acid phosphatase did not alter the permeation of any of these compounds. Phospholipase A2 significantly enhanced permeation of benzoic acid and mannitol while it did not have any effect on the penetration of testosterone. These results for the first time demonstrate that enzymes may remarkably affect and/or regulate the permeation of topically applied compounds.
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PMID:Epidermal enzymes as penetration enhancers in transdermal drug delivery? 869 22

1. The defective Cl- secretion characteristic of cystic fibrosis airway epithelial cells can be bypassed by an alternative Ca2+ dependent Cl- secretory pathway that is activated by extracellular nucleotides, e.g. uridine-5'triphosphate (UTP), acting on P2U purinoceptors. Since UTP is susceptible to hydrolysis by nucleotidases and phosphatases present in the airways, the identification of stable P2U-purinoceptor agonists would be of therapeutic relevance. 2. Uridine-5'-O-(3-thiotriphosphate) (UTP gamma S) was synthesized by nucleoside diphosphate kinase-catalyzed transfer of the gamma-phosphorothioate from guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S) or adenosine-5' = O-(3-thiotriphosphate) (ATP gamma S) to UDP. Formation of UTP gamma S was illustrated by observation of transfer of 35S from [35S]-GTP gamma S and transfer of 3H from [3H]-UDP. The chemical identity of high performance liquid chromatography (h.p.l.c.)-purified UTP gamma S was confirmed by nuclear magnetic resonance analysis. 3. Human 1321N1 astrocytoma cells stably expressing the phospholipase C-coupled human P2U-purinoceptor were utilized to test the activity of UTP gamma S. UTP gamma S (EC50 = 240 nM) was essentially equipotent to UTP and ATP for stimulation of inositol phosphate formation. 4. Unlike [3H]-UTP, [3H]-UTP gamma S was not hydrolyzed by alkaline phosphatase, acid phosphatase, or apyrase. Moreover, no hydrolysis was detected during a 1 h incubation with human nasal epithelial cells. 5. UTP gamma S was equally potent and efficacious with UTP for stimulation of Cl- secretion by human nasal epithelium from both normal donors and cystic fibrosis patients. Based on its high potency and resistance to hydrolysis, UTP gamma S represents a promising compound for treatment of cystic fibrosis.
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PMID:Enzymatic synthesis of UTP gamma S, a potent hydrolysis resistant agonist of P2U-purinoceptors. 882 64

The cells of Burkholderia pseudomallei, B. cepacia and Pseudomonas aeruginosa grown on agar plates were stained with fluorescently-labeled insulin. The former two species were stained positively indicating insulin binding but P. aeruginosa was not. Insulin exposure reduced phospholipase C and acid phosphatase activities of B. pseudomallei but did not affect those enzymatic activities of B. cepacia in the employed experimental conditions. It is suggested that B. pseudomallei have insulin receptors which may be associated with a signal transfer system involving phospholipase and protein tyrosine phosphatase.
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PMID:Affinity and response of Burkholderia pseudomallei and Burkholderia cepacia to insulin. 918 75

In Kluyveromyces lactis, the cell wall compositions of Kl (ATCC 96897), a wild sensitive strain, and Klm (ATCC 96896), a strain resistant to amphotericin B (AmB), were shown to be very different, since the walls in the latter were significantly enriched in hexosamine, but had a reduced content in phosphate and amino acid. In both strains, the cell walls limited their sensitivity to this antifungal agent. The absence of cell wall increased the sensitivity of the cells to this polyene by 5 to 10-fold. When the cells were treated with enzymes such as pronase and chitinase in order to change the cell wall structure just before inoculation, the yeasts appeared more resistant to the antibiotic. However, treatments with chymopapain and phospholipase C did not significantly change the sensitivity of the two strains to this agent. Cells treated with acid phosphatase displayed a longer lag phase than the control cells. In addition, when cultured in the presence of AmB, the cells were less sensitive to this agent. The present results reveal that both a change in the ionic charges of the cell wall and an alteration in the cell wall structure modified the sensitivity of these yeast strains to AmB.
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PMID:Implication of cell wall constituents in the sensitivity of Kluyveromyces lactis strains to amphotericin B. 976 14

An acid phosphatase (AP) and a phosphorylcholine hydrolase (PCH) were detected in excretory-secretory (ESP) products from adult Haemonchus contortus. The AP had a pH optimum of 4.5 and was inhibited by tartaric acid and sodium fluoride, but not by o-phenanthroline. The AP hydrolyzed paranitrophenol (pnp)-phosphate and to a lesser extent pnp-phenyl-phosphonate but did not hydrolyze diester substrates. Purified AP consisted of heterodimers with relative molecular weight (Mr) of 41.9 and 48.7 kDa and had a native molecular weight of 98 kDa by size-exclusion chromatography (SEC). The PCH had a pH optimum of about 9.5 and was inhibited by EDTA and o-phenanthroline but not by the specific phospholipase inhibitor D609. The specific activity of PCH in the ESP was approximately 25-fold less than that of AP. PCH also hydrolyzed 5'-thymidine monophosphate-pnp at a rate about 40% lower than pnp-phosphorylcholine but did not hydrolyze 3'-thymidine monophosphate-pnp. Partial purification of PCH suggests an Mr of 50.2 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an Mr of 102 kDa by SEC. Both AP and PHC were secreted in vitro in a time-dependent manner and had their highest concentrations in the intestine. The results indicate that H. contortus adults secrete significant amounts of AP that might be a digestive enzyme. PCH is also an intestinal enzyme and is secreted in lesser amounts than AP. The PCH is probably not a phospholipase C but has some characteristics of a type I phosphodiesterase.
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PMID:Characterization of acid phosphatase and phosphorylcholine hydrolase in adult Haemonchus contortus. 1070 55

The pharmacological profile of metabotropic glutamate receptor (mGluR) activation of phospholipase D (PLD), and the associated signalling pathways, were examined in rat cerebrocortical synaptosomes. The assay was conducted using a transphosphatidylation reaction in synaptosomes which were pre-labelled with either [(3)H]-arachidonic acid or [(32)P]-orthophosphate. The mGluR agonists (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1S, 3R-ACPD) and (RS)-3,5-dihydroxyphenylglycine (DHPG), both activated PLD, while phorbol 12,13-dibutyrate (PDBu) treatment caused receptor-independent activation of PLD and had an additive effect on 1S,3R-ACPD induced PLD activity. A protein kinase C (PKC) inhibitor, GF109203X, failed to antagonize mGluR receptor-coupled PLD activity. We could not detect any increase in the products of PI (phosphoinositide)-specific phospholipase C (PI-PLC), inositol(1,4, 5)trisphosphate or diacylglycerol, by 1S, 3R-ACPD at 15 s. However, diacylglycerol increased monophasically in response to mGluR agonists and remained elevated for at least 15 min. Phosphatidic acid phosphohydrolase (PAP) activity, which converts PA to DAG, was present in the synaptosomes. These data suggest that, in rat cerebrocortical synaptosomes, the 1S,3R-ACPD-sensitive mGluR is coupled to PLD through a mechanism that is independent of both PKC and PI-PLC.
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PMID:Activation of phospholipase D by metabotropic glutamate receptor agonists in rat cerebrocortical synaptosomes. 1105 24

Peritoneal and bronchoalveolar macrophages activated in vitro by endotoxin, exhibit alterations in the acid phosphatase activity of cell lysates when certain hormones or autacoids are present in the culture medium. They also show morphological changes concerning general appearance and acid phosphatase cytochemistry. Certain agents known to increase the intracellular levels of cyclic AMP, such as dopamine and prostaglandin E2, decreased this enzyme activity in the lysates of peritoneal macrophages. Adrenalin had no effect on this activity at 14 hours, but was found to increase the activity in the culture medium at the initial hours of incubation. Glucagon decreased whereas insulin increased acid phosphatase activity in bronchoalveolar macrophages. Serotonin or histamine, known to activate phospholipase C, increased this activity in peritoneal or bronchoalveolar macrophages. The results of this study, taken together with previously published data (Kondomerkos et al., 2003), suggest that hormones and autacoids may control certain parameters of macrophage activation including acid phosphatase activity.
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PMID:In vitro effects of hormones and autacoids on the activity of acid phosphatase in the lysates of endotoxin-activated rat peritoneal and bronchoalveolar macrophages. 1297 79

We recently reported that cultivation of oat (Avena sativa L.) without phosphate resulted in plasma membrane phosphoglycerolipids being replaced to a large extent by digalactosyldiacylglycerol (DGDG) (Andersson, M. X., Stridh, M. H., Larsson, K. E., Liljenberg, C., and Sandelius, A. S. (2003) FEBS Lett. 537, 128-132). We report here that DGDG is not the only non-phosphorous-containing lipid that replaces phospholipids but that also the content of glucosylceramides and sterolglycosides increased in plasma membranes as a response to phosphate starvation. In addition, phosphate deficiency induced similar changes in lipid composition in the tonoplast. The phospholipid-to-glycolipid replacement apparently did not occur to any greater extent in endoplasmic reticulum, Golgi apparatus, or mitochondrial inner membranes. In contrast to the marked effects on lipid composition, the polypeptide patterns were largely similar between root plasma membranes from well-fertilized and phosphate-limited oat, although the latter condition induced at least four polypeptides, including a chaperone of the HSP80 or HSP90 family, a phosphate transporter, and a bacterial-type phosphoesterase. The latter polypeptide reacted with an antibody raised against a phosphate deficiency-induced phospholipase C from Arabidopsis thaliana (Nakamura, Y., Awai, K., Masuda, T., Yoshioka, Y., Takamiya, K., and Ohta, H. (2005) J. Biol. Chem. 280, 7469-7476). In plasma membranes from oat, however, a phospholipase D-type activity and a phosphatidic acid phosphatase were the dominant lipase activities induced by phosphate deficiency. Our results reflect a highly developed plasticity in the lipid composition of the plasma membrane and the tonoplast. In addition, phosphate deficiency-induced alterations in plasma membrane lipid composition may involve different sets of lipid-metabolizing enzymes in different plant tissues or species, at different stages of plant development and/or at different stages of stress adjustments.
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PMID:Phosphate-limited oat. The plasma membrane and the tonoplast as major targets for phospholipid-to-glycolipid replacement and stimulation of phospholipases in the plasma membrane. 1592 62


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