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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Male Wistar rats were fed a high fat diet (HFD) containing 2.5% cholesterol and 16% lard supplemented with polyphenolic natural products namely quercetin, morin or tannic acid (100 mg/rat/day) for 4, 7 and 10 wk. Rats fed HFD without the supplements served as control. The effects of these compounds on blood lipid profiles, enzymes, liver fat and aorta of the rat were studied. In rats fed HFD containing tannic acid, plasma total cholesterol (TC), low density lipoprotein cholesterol (LDLC) and triglyceride (TG) were reduced by 33.3%, 29.6% and 65.1%, respectively, at week 10. High density lipoprotein cholesterol (HDLC) concentration was not altered. Fat deposition was also decreased in the liver of these rats. Morin significantly reduced plasma TG (65.1%) and liver fat only at week 7 while at week 10 it reduced plasma TC and LDLC by 30.9% and 29.3% respectively. The plasma HDLC concentration was increased by 47.3% at week 4 but no effect was seen at weeks 7 and 10. In the rats fed HFD containing quercetin, plasma HDLC was increased by 28.6% at week 7 but at week 10, plasma LDLC was increased by 21.2%. Quercetin did not cause any significant changes on the plasma TC, TG and liver fat at weeks 4, 7 and 10. Plasma alanine aminotransferase, alkaline phosphatase and bilirubin in control and treated groups were not significantly different. However, hepatic lipase activity in rats fed tannic acid was significantly lower. Aortae of all groups of rats showed no abnormalities. The present report indicates that tannic acid and morin are effective in reducing plasma and liver lipids when supplemented with a high fat diet in rats.
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PMID:Effects of polyphenolic natural products on the lipid profiles of rats fed high fat diets. 152 62

Phosphatidylinositol 4-phosphate (PIP) kinase (E.C. 2.7.1.68) has been purified about 1200-fold from rat liver plasma membranes, taking advantage of affinity chromatography on quercetin-Sepharose as a novel step. The purified PIP kinase showed no contamination by the following enzyme activities: phosphatidylinositol (PI) kinase (EC 2.7.1.67), protein kinase C (EC 2.7.1.-), diacylglycerol kinase (EC 2.7.1.-), phospholipase C (EC 3.1.4.11), protein-tyrosine kinase (EC 2.7.1.112), alkaline phosphatase (EC 3.1.3.1), triphosphoinositide phosphomonoesterase (EC 3.1.3.36), adenylate kinase (EC 2.7.4.3) and cAMP-dependent protein kinase (EC 2.7.1.37). The liver membrane enzyme requires high Mg2+ concentrations with a KM value of 10 mM. Ca2+ or Mn2+ could replace Mg2+ to a certain, though small, extent. Apparent KM values with respect to PIP and ATP were 10 and 65 microM, respectively. GTP was slightly utilized by the kinase as phosphate donor while CTP was not. Quercetin inhibited the enzyme with Ki = 34 microM. Extending our previous observations (Urumow, T. and Wieland, O.H. (1986) FEBS Lett. 207, 253-257 and Urumow, T. and Wieland, O.H. (1988) Biochim. Biophys. Acta 972, 232-238) [gamma S]pppG still stimulated the PIP kinase in extracts of solubilized liver membranes. 20-40% (NH4)2SO4 precipitation of the membrane extracts yielded a fraction that contained the bulk of enzyme activity but did not respond to stimulation by [gamma S]pppG any longer. This was restored by recombination with a protein fraction collected at 40-70% (NH4)2SO4 saturation, presumably containing a GTP binding protein and/or some other factor separated from the PIP kinase. In the reconstituted system [gamma S]pppG stimulated PIP kinase in a concentration dependent manner with maximal activation at 5 microM. This effect was not mimicked by [gamma S]pppA and was blocked by [beta S]ppG. These results strongly support our view that in liver membranes PIP kinase is regulated by a G-protein.
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PMID:Purification and partial characterization of phosphatidylinositol-4-phosphate kinase from rat liver plasma membranes. Further evidence for a stimulatory G-protein. 215 97

Complete as well as incomplete (second stage) tumor promoters increase alkaline phosphatase (AP) activity in mouse epidermis in vivo but not in vitro. This indicates that the high level of AP in epidermis after application of a tumor promoter arises from an extraepidermal site, possibly from leaky endothelial cells of promoter-damaged blood vessels. Quercetin, which is known to stabilize the microvasculature as well as to inhibit tumor promotion, very effectively suppresses tumor promoter-stimulated AP activity. Quercetin is also a potent inhibitor of calcium, phospholipid-dependent protein kinase (Ca, PL-PK). Since inhibitors of other enzymes also suppressible by quercetin are ineffective, the damage of microvasculature and the increase in AP activity in epidermis might be Ca, PL-PK mediated effects of tumor promoters.
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PMID:Stimulation of alkaline phosphatase activity in mouse epidermis by tumor promoters. 670 49

When 7721 human hepatocarcinoma cells were treated with 100 nM phorbol-12-myristate-13-acetate (PMA), the activity of N-acetylglucosaminyltransferase V(GnT-V) in the cells varied in accordance with the activity of membranous protein kinase C (PKC), but not with that of cytosolic PKC. Quercetin, a non-specific inhibitor of Ser/Thr protein kinase, and D-sphingosine and staurosporine, two specific inhibitors of PKC, blocked the activation of membranous PKC and GnT-V by PMA. Among the three inhibitors, quercetin was least effective. The inhibitory rates of quercetin and staurosporine toward membranous PKC and GnTV were proportional to the concentrations of the two inhibitors. The activities of GnTV and membranous protein kinase A (PKA) were also induced in parallel by dibutyryl cAMP (db-cAMP) and this induction was blocked by a specific PKA inhibitor. When cell free preparations of 7721 cells and human kidney were treated with alkaline phosphatase (ALP) to remove the phosphate groups, the GnTV activities were decreased. These results suggest that GnTV may be activated by membranous PKC or PKA, indirectly or directly, via phosphorylation of Ser/Thr residues.
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PMID:Regulation of N-acetylglucosaminyltransferase V by protein kinases. 874 53

The efficacy of mannosylated liposome formulations with Quercetin (QC, a flavonoid antioxidant isolated from indigenous origin) has been tested in vivo against carbon tetrachloride(CCl(4))-induced liver oxidative damage in rats. Single subcutaneous injection of CCl(4) (40% v/v in olive oil; 1 ml/kg) induces the generation of toxic oxygen radicals and results in hepatocellular damage. The increased serum enzyme levels (glutamate pyruvate transaminase, alkaline phosphatase) and hepatocellular conjugated diene levels by CCl(4) induction were significantly lowered due to pretreatment with mannosylated liposomal QC (MLQ) (0.5 ml liposomal suspension containing 0.27 mg QC), whereas the same amount of free QC was found to be ineffective. In addition, the effectiveness of MLQ on CCl(4)-induced acute liver damage also was evaluated by tissue histopathological examination. Damage produced by CCl(4) in liver reverted to normal with pretreatment of MLQ.
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PMID:Targeting of liposomal flavonoid to liver in combating hepatocellular oxidative damage. 1239 35

It is possible that the flavonoids that are found in many foods might have a protective effect against osteoclastic activity. However, little information is available about the effects of flavonoids on osteoblastogenesis. Therefore, we investigated the effects of quercetin, a flavonoid, on the metabolism of rat calvarial osteoblast-like cells (ROB cells) in culture. The proliferation of cells was markedly inhibited upon exposure of cells to quercetin at 5 x 10(-6) to 1 x 10(-5) M. Quercetin at 1 x 10(-5) M did not induce apoptosis in ROB cells but arrested cells at the G1 phase of the cell cycle. In addition, quercetin stimulated the expression of mRNA for p21(waf1/cip1), which inhibits the activity of cyclin-dependent kinases, and inhibited the phosphorylation of histone H1. Furthermore, after cells had ceased to proliferate, quercetin reduced the activity of alkaline phosphatase, the level of expression of mRNA for osteocalcin, the rate of deposition of Ca(2+), and the formation of mineralized nodules, all of which are markers of osteoblast differentiation. These findings indicate that quercetin inhibits the proliferation, differentiation, and mineralization of osteoblastic cells.
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PMID:Quercetin, a flavonoid, inhibits the proliferation, differentiation, and mineralization of osteoblasts in vitro. 1475 27

A high dietary intake of plant foods is thought to contribute to the prevention of colorectal cancers in humans and flavonoids as part of such a diet are considered to contribute to those protective effects. Quercetin is a major dietary flavonoid consumed with a diet rich in onions, tea, and apples. We used HT-29 human colon cancer cells and investigated the effects of quercetin on proliferation, apoptosis, and differentiation as processes shown to be disregulated during cancer development. To identify the cellular targets of quercetin action, two-dimensional gel electrophoresis was performed and proteins altered in expression level after quercetin exposure of cells were identified by mass spectrometry of peptide fragments generated by tryptic digestion. Quercetin inhibited the proliferation of HT-29 cells with an IC(50)-value of 81.2 +/- 6.6 microM. Cell differentiation based on surface expression of alkaline phosphatase was enhanced 4-fold and the activity of the pro-apoptotic effector caspase-3 increased 3-fold. Those effects were associated with the regulation of heat-shock proteins and annexins shown to both play a crucial role in the process of apoptosis. Cytoskeletal caspase substrates were found as regulated as well and various proteins involved in intermediary metabolism and in gene regulation showed altered steady-state expression levels upon quercetin treatment of cells. In conclusion, quercetin alters the levels of a variety of proteins involved in growth, differentiation, and apoptosis of colon cancer cells. Their identification as molecular targets of quercetin may explain the anti-cancer activities of this flavonoid.
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PMID:Protein expression profiling identifies molecular targets of quercetin as a major dietary flavonoid in human colon cancer cells. 1522 76

The present study was designed to investigate the effects of quercetin on oxidative stress and activation of nuclear factor kappa B (NF-kappaB) in an experimental model of portal hypertensive gastropathy induced by partial portal vein ligation (PPVL). Portal pressure was significantly elevated in PPVL rats. Transaminase and alkaline phosphatase activities were not significantly modified, indicating absence of liver injury. Histological analysis of gastric sections showed a lost of normal architecture, with edema and vasodilatation. The cytosolic concentration of thiobarbituric acid reactive substances and the lipoperoxidation measurement by chemiluminiscence were significantly increased. Superoxide dismutase activity in gastric mucosa was significantly reduced. Portal hypertensive gastropathy induced a marked activation of NF-kappaB, accompanied by a decrease in IkappaB protein levels and a significant induction of nitric oxide synthase (iNOS) protein. Administration of quercetin markedly alleviated histological abnormalities and inhibited oxidative stress and NF-kappaB activation. IkappaB decrease and induction of iNOS protein were partially prevented by quercetin. Quercetin treatment, by abolishing the NF-kappaB signal transduction pathway, may block the production of noxious mediators involved in the pathogenesis of portal hypertensive gastropathy.
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PMID:Quercetin prevents oxidative stress and NF-kappaB activation in gastric mucosa of portal hypertensive rats. 1547 65

Flavonoids, which have been detected in a variety of foods, have been repeatedly reported to affect bone metabolism. However, the effects of flavonoids on osteoblastogenesis remain a matter of some controversy. In this study, the effects of quercetin on the differentiation and proliferation of human adipose tissue-derived stromal cells (hADSC) were determined. Quercetin was found to increase osteogenic differentiation in a dose-dependent manner. Other flavonoids, chrysin and kaempferol, were also shown to increase the osteogenic differentiation of hADSC, but this stimulatory effect was weaker than that associated with quercetin. Quercetin pretreatment administered prior to the induction of differentiation also exerted stimulatory effects on the osteogenic differentiation of hADSC. RT-PCR and real time PCR analysis showed that quercetin treatment induced an increase in the expression of osteopontin, BMP2, alkaline phosphatase and Runx2. Quercetin inhibited the proliferation of hADSC, but did not affect their survival. The pretreatment of quercetin increased ERK phosphorylation during osteogenic differentiation, although it did not increase ERK activity in control culture condition. ICI182780, an specific estrogen receptor antagonist, failed to inhibit the effects of quercetin on osteogenic differentiation. Quercetin-pretreated hADSC showed better bone regenerating ability in skull defect model of nude mice than naive cells. Our findings indicate that quercetin enhances osteogenic differentiation via an independent mechanism from estrogen receptor (ER) activation, and prove useful for in vivo bone engineering, using human mesencymal stem cells (hMSC).
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PMID:Quercetin, a flavonoid, inhibits proliferation and increases osteogenic differentiation in human adipose stromal cells. 1699 34

Quercetin is a flavonol, also a phytoestrogen, available commonly in onion and apple. Our laboratory investigated its effect on MC3T3-E1 cells' alkaline phosphatase activity in vitro and compared the amount of new bone produced by quercetin in collagen matrix to that produced by bone grafts and collagen matrix in vivo. Four bone defects, 5mm by 10mm were created in the parietal bone of 2 New Zealand White rabbits. In the experimental animal, 2 defects were grafted with quercetin solution mixed with collagen matrix. In the control animal, 2 defects were grafted with collagen matrix alone. Animals were killed on day 14 and the defects were dissected and prepared for histological qualitative assessment. Results showed that 10muM of quercetin increased alkaline phosphatase activity of MC3T3-E1 cells at 72 hours in vitro by 32%. In the experimental animal, there was new bone growing inside the bone defects. In conclusion, specific concentration of quercetin increased alkaline phosphatase activity of MC3T3-E1 cells in vitro and quercetin in collagen matrix has the effect of forming new bone across bone defects in vivo.
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PMID:Effect of quercetin on preosteoblasts and bone defects. 1946 27


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