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)

To show adenylate cyclase (AC) activity in rat calvaria, it is necessary first to decalcify the specimen. In hard tissues, several enzymes (adenosine triphosphatase (ATPase), alkaline phosphatase (APase), adenylate cyclase (AC) and perhaps pyrophosphatase (PPiase) are able to degrade adenosine triphosphate (ATP). The presence of sodium fluoride (NaF) in the incubation medium reduces the quantity of precipitate formed, compared to that observed using a NaF-free incubation medium. Levamisole, used under the same conditions, gives similar results. Possibly NaF inhibits pyrophosphohydrolase and/or phosphatases which mask the AC activity. Adenylylimidophosphate (AMP-PNP), which is a specific AC substrate, confirms the results obtained with ATP. AC activity is demonstrated cytochemically in the osteoblast and preosteoblast membranes, at the junction between two osteoblasts and along the cytoplasmic processes of the osteoblast which penetrate into the osteoid matrix. The osteocytes never show a precipitate, except those which present some osteoblastic features and then only on the membrane facing the osteogenic layer. An intracellular reaction is also evident and is discussed. Parathyroid hormone (PTH) does not reveal new sites of AC activity but increases the quantity of precipitate observed.
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PMID:An attempt at localizing adenylate cyclase in rat calvaria. Influence of sodium fluoride and parathyroid hormone. 700 93

In mammals there are two forms of alkaline phosphatase, one of which is widely distributed in a variety of tissues, and one of which is confined to intestine. Levamisole (1-tetramisole) inhibits the nonintestinal form of the enzyme, but is without effect on the intestinal form. We have exploited this difference by using conjugates made with calf intestinal alkaline phosphatase for immunohistochemical demonstration of H2 antigens in frozen section of mouse tissues. The alkaline phosphatase staining is performed in the presence of 1 mm levamisole, which inhibits the endogenous tissue enzyme without loss of staining by the conjugate. Endogenous enzyme can be inhibited by other means, such as exposure to 20% acetic acid, but labile antigens may be destroyed.
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PMID:Inhibition of endogenous tissue alkaline phosphatase with the use of alkaline phosphatase conjugates in immunohistochemistry. 702 2

The effects of alkaline phosphatase inhibitors (levamisole, L-bromotetramisole) on the activity of the enzyme and on calcification in vitro were studied, to find out whether there is a relationship between alkaline phosphatase and calcification. Metatarsal bones of 15 1/4-day-old embryonic mice were dissected and cultured for 40 hours in the presence and absence of inhibitor. Levamisole and L-bromotetramisole fully inhibited calcification in vitro when present in concentrations which almost totally inhibited alkaline phosphatase activity, as measured biochemically or histochemically. However, incorporation of 3H-thymidine and 35S-sulphate was also inhibited. Furthermore, D-bromotetramisole, the dextroform of bromotetramisole which has no effect on alkaline phosphatase, inhibited calcification and 3H-thymidine and 35S-sulphate incorporation as well. The results of this study show that these inhibitors cannot be used to study the relationship between alkaline phosphatase and calcification. In addition, they suggest that although alkaline phosphatase may be important for the process of calcification, it is probably not a critical factor.
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PMID:Alkaline phosphatase and calcification, correlated or not? 726 67

We studied (1) the effect of primary modulators of phosphate transport, namely the hypophosphataemic mouse mutant (Hyp) and low-phosphorus diet, on alkaline phosphatase activity in mouse renal-cortex brush-border membrane vesicles and (2) the effect of several primary inhibitors of alkaline phosphatase on phosphate transport. Brush-border membrane vesicles from Hyp-mouse kidney had 50% loss of Na+-dependent phosphate transport, but only 18% decrease in alkaline phosphatase activity. The low-phosphorus diet effectively stimulated Na+/phosphate co-transport in brush-border membrane vesicles (+ 118%), but increased alkaline phosphatase activity only slightly (+13%). Levamisole (0.1 mM) and EDTA (1.0 mM) inhibited brush-border membrane-vesicle alkaline phosphatase activity of 82% and 93% respectively, but had no significant effect on Na+/phosphate co-transport. We conclude that alkaline phosphatase does not play a direct role in phosphate transport across the brush-border membrane of mouse kidney.
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PMID:Alkaline phosphatase activity does not mediate phosphate transport in the renal-cortical brush-border membrane. 747 62

A single step extraction procedure for recovery of the anthelmintic drug levamisole (LEV) from aqueous solutions and calf serum was evaluated. Levamisole was extracted from aqueous solutions and calf serum with 1.5 ml of ethyl acetate. After evaporation to dryness, the LEV content of extracts was estimated by measuring LEV inhibition of bovine milk fat globule membrane alkaline phosphatase. Lipid interference with absorbance readings was eliminated by the addition of 1.0 ml of chloroform to the assay mixtures. The recovery of LEV from both aqueous samples and serum samples by this single step extraction procedure coupled with enzymatic assay was 90%. The effective range for serum LEV determination was 0.3 to 20 micrograms/ml.
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PMID:Evaluation of a single step extraction procedure for enzymatic assay of levamisole in calf serum. 809 Oct 9

The IEC-6 cell line was derived from newborn rat small intestinal crypts and maintains characteristics of nontransformed crypt epithelial cells. We have reported that alkaline phosphatase (ALP) activity, a differentiation marker for intestinal epithelial cells, is regulated in IEC-6 cells by 1,25-dihydroxycholecalciferol (1,25(OH)2D3). Using reverse transcription polymerase chain reaction, we determined that the ALP in IEC-6 cells is the liver/bone/kidney ALP (LALP) isoenzyme and not the mature enterocyte form. Levamisole, a specific blocker for LALP, blocked the ALP activity of IEC-6 cells. Kinetic studies showed that 1,25(OH)2D3 increases Vm values of ALP in IEC-6 cells while Km values remain the same. Northern analysis of LALP mRNA levels in IEC-6 cells indicated that 10(-7) M 1,25(OH)2D3 acts by increasing alkaline phosphatase activity at the gene expression level.
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PMID:Identification of vitamin D-stimulated alkaline phosphatase in IEC-6 cells, a rat small intestine crypt cell line. 818 27

The ability of Levamisole to decrease mineralization in skeletal tissue is usually related to its effect on alkaline phosphatase (ALP). However, Levamisole is also suspected to diminish mineralization by an additional mechanism which is unrelated to the ALP control of apatite crystal growth. To delineate the time in differentiation during which Levamisole inhibits mineralization, a tissue culture model system of bone marrow stromal cells was used. Secondary cultures of stromal cells were propagated in osteoprogenitor cell (OPC) induction medium for three weeks, followed by measurement of calcium precipitation. In situ ALP assays at pH 7.6 were also performed. When cells were cultured with 0.2 mM Levamisole for three weeks, Day 20 values of calcium precipitates were lower than in controls, but Day 20 ALP values were paradoxically higher. The correlation between calcium and ALP within each group was low. The correlation slightly improved, in uninhibited cultures, when Day 21 calcium values were matched with earlier Day 12 ALP values. This suggested the existence of a Levamisole-sensitive mechanism for mineralization inhibition effective prior to the culture's mineralization stage. To focus on this early effect on mineralization Levamisole was added to stromal cultures on different days and removed on Day 12. Levamisole decreased Day 21 mineralization when added on Days 0, 3, 5, and 7, but not when added on Day 9. The Levamisole-induced inhibition of mineralization was accompanied by an increase in Day 12 ALP specific activity, compared to controls, when added from Day 5 and thereafter. The results indicate that part of the ability of stromal cells to mineralize is determined during the first week of culture.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Studies of the levamisole inhibitory effect on rat stromal-cell commitment to mineralization. 822 84

The purpose of this study was to investigate how levels of gingival crevicular fluid (GCF) alkaline phosphatase (ALP) change in relation to levels of plaque and gingival inflammation in 20 adults during a 21 day period of experimental gingivitis. The source of ALP within GCF was also investigated using a repeat sampling protocol; by determining enzyme levels derived from 30 putative periodontal pathogenic and non-pathogenic species; and by examining inhibition profiles from a variety of host and bacterial ALP isoenzymes. Total 30-s GCF ALP levels increased significantly (p < 0.002) during experimental gingivitis and preceded an increase in gingival index (GI) by approximately 7 days. Enzyme levels correlated with GCF volume (R = 0.7; p < 0.0001), but repeat sampling indicated that entry of ALP into the gingival crevice was independent of the rate of fluid flow. Only 5 of the bacterial species investigated produced clearly detectable levels of ALP in culture supernatants, these were P. gingivalis (381), P. intermedia (581), P. nigrescens (8944), Dentin P. gingivalis (TW 471: clinical isolate) and C. ochracea (25). Levamisole inhibition and studies on suspensions of washed plaque demonstrated that host-derived ALP contributed to > 80% of the enzyme in GCF. We conclude that elevated 30-s GCF ALP levels measured using the chemiluminescent assay reported, are detectable before increases in gingival indices and appear to be a better marker of gingival inflammation than ALP concentrations. The major source of ALP within GCF is host derived and in early inflammatory disease is likely to be of polymophonuclear leukocyte origin.
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PMID:Chemiluminescent assay of alkaline phosphatase in human gingival crevicular fluid: investigations with an experimental gingivitis model and studies on the source of the enzyme within crevicular fluid. 881 80

Levamisole inhibits alkaline phosphatase (ALP) activity in kidney brush border membranes and increases phosphate excretion in vivo in dogs and rats. I-p-Bromotetramisole (I-BR) is a more potent analog of levamisole in regard to inhibition of ALP activity in vitro, but had no effect on phosphate transport by in vitro proximal tubules of the rabbit. Since its effect on phosphate excretion in vivo has not been studied, the present study tested the effects of infusion of I-BR on phosphate excretion in Sprague-Dawley rats. Fractional excretion of phosphate (FEPi) was measured in thyroparathyroidectomized Sprague-Dawley rats before and during a systemic infusion at 0.8 ml/min of 10 mM I-p-Bromotetramisole oxalate (I-BR, n = 6), or the inactive isomer d-p-Bromotetramisole oxalate (d-BR, n = 5). The FEPi increased significantly from 4.7% +/- 0.9% to 13.4% +/- 3.1% in response to I-BR whereas there were no changes in FEPi with inactive d-BR. In conclusion, systemic infusion of I-p-Bromotetramisole increases FEPi in Sprague-Dawley rats.
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PMID:Effect of bromotetramisole on renal phosphate excretion. 893 64

In the present report we describe an ATP diphosphohydrolase (apyrase EC 3.6.1.5) in rat cardiac sarcolemma. It is Ca2+ dependent and is insensitive to ouabain, orthovanadate, N-ethylmaleimide (NEM), lanthanum, and oligomycin that are classical ATPase inhibitors. Sodium azide that is a mitochondrial inhibitor at low concentrations, did not affect the enzyme activity at 5.0 mM or below. In contrast, at high concentrations (> 10 mM) sodium azide inhibited the enzyme. Levamisole, a specific inhibitor of alkaline phosphatase and P1, P5-di(adenosine 5'-)pentaphosphate (Ap5A), a specific inhibitor of adenylate kinase did not inhibit the enzyme. Mercury chloride showed a parallel inhibition of the hydrolysis of both substrates of apyrase. Similar inhibition profiles are powerful evidence for a common catalytic site for the hydrolysis of both substrates. The enzyme has an optimum pH range of 7.5-8.0 and catalyzes the hydrolysis of triphospho- and diphosphonucleosides other than ATP or ADP. The apparent Km (Michaelis constant) and Vmax (maximal velocity) are 62.1 +/- 5.2 microM and 1255.7 +/- 178 micromol inorganic phosphate liberated/min/mg with ATP and 59.4 +/- 4.3 microM and 269.2 +/- 39 micromol inorganic phosphate liberated/min/mg with ADP. Enzyme markers indicated that this apyrase is associated with the plasma membrane. A deposition of lead phosphate granules on the outer surface of the sarcolemmal vesicles was observed by electron microscopy in the presence of either ATP or ADP as substrate. It is suggested that the ATP diphosphohydrolase could regulate the concentration of extracellular adenosine, and thus is important in the control of vascular tone and coronary flow.
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PMID:Characterization and localization of an ATP diphosphohydrolase activity (EC 3.6.1.5) in sarcolemmal membrane from rat heart. 914 25


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