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)

Rat matrix-induced alkaline phosphatase is an enzyme which requires magnesium and zinc ions for its maximal activity. Two Zn(II) ions and one Mg(II) ion are bound to each subunit of native dimeric enzyme. The presence of magnesium ion (10-100 microM) or zinc ion (7-20 nM) alone is sufficient to stimulate apoenzyme activity. However maximal activity (264 U/mg) requires the presence of both ions. Binding of Zn(II) ions to the Mg(II) binding site causes a strong inhibition of the apoenzyme while the binding of Mg(II) on Zn(II) binding site is not sufficient to stimulate PNPPase activity of the apoenzyme. Binding of both ions to the enzyme molecule did not change the apparent dissociation constant for PNPP hydrolysis.
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PMID:Effect of Zn(II) and Mg(II) on phosphohydrolytic activity of rat matrix-induced alkaline phosphatase. 261 37

1. The kinetic properties of the p-nitrophenylphosphatase (EC 3.1.3.1) from erythrocytes was investigated in DMD-patients and DMD-carriers. 2. A different allosteric behaviour in the p-nitrophenylphosphatase from DMD-patients and DMD-carriers compared to controls is supported by the following findings: (a) values of n altered in F- inhibition of (K+)-activated p-nitrophenylphosphatase with Hill coefficients -1.5, -2.2 and -3.1; (b) heterotropic effect of increased concentration of Mg2+ on F- inhibition which is reverted by K+ in DMD-carriers and in control, but not in DMD-patients. 3. Evidence is presented showing that in DMD-patients and in DMD-carriers the interaction membrane-enzyme is different from the corresponding controls.
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PMID:Allosteric transition of erythrocyte alkaline phosphatase from Duchenne muscular dystrophy (DMD) patients and Duchenne muscular dystrophy carriers (Homo sapiens). 284 81

Enzyme histochemical techniques were utilized to examine the progression and extent of proximal tubular injury during the development of cis-diamminedichloroplatinum (II) (CDDP)-induced acute renal failure. Acute renal failure was induced in male rats by the intraperitoneal administration of 10 mg CDDP/kg body weight. At 6, 24, 48, 72, and 96 hr following treatment, renal function was assessed and tissue was collected for renal morphologic and enzyme histochemical studies. The enzymes examined were gamma-glutamyl transpeptidase, alkaline phosphatase, sodium-potassium ATPase (nitrophenyl phosphatase), acid phosphatase, glucose-6-phosphatase, succinic dehydrogenase, alpha-glycerophosphate dehydrogenase, and lactic dehydrogenase. By 24 hr, the activity of acid phosphatase was reduced throughout the proximal tubule, with the greatest decrease occurring in the P3 segment of the proximal tubule located in the outer stripe of the outer medulla. Changes in the histochemical staining of the remaining enzymes were not consistently observed until 48 or, in some cases, 72 hr. These alterations involved all portions of the proximal tubule with the most severe changes involving P3. The results of the enzyme histochemical studies along with the morphologic findings indicating that the initiation of CDDP-induced acute renal failure, first apparent at 48 hr in this model, is associated with cell injury throughout the proximal tubule. The majority of the histochemical changes did not become apparent until late in the course of tubular injury. This suggests that most of the changes in enzyme activity represent nonspecific effects of CDDP-induced tubular injury, as opposed to direct enzyme inhibition by the drug.
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PMID:Cis-diamminedichloroplatinum (II)-induced acute renal failure in the rat: enzyme histochemical studies. 287 24

The expression and cytochemical localization of alkaline phosphatase and Na+-pump sites were investigated in the human adenocarcinoma cell line HT-29.18 during differentiation. In the undifferentiated state, HT-29.18 cells expressed ATPase activity on plasma membrane whereas they displayed no alkaline phosphatase activity. In differentiated HT-29.18 cells, strong alkaline phosphatase activity was present on the apical membrane, whereas ATPase activity was restricted to the basolateral membrane. Intra- and intercellular lumina (cysts) observed in undifferentiated cells were devoid of both enzyme activities. In differentiated cells, cysts bearing well developed microvilli were strongly positive for alkaline phosphatase activity, while this activity seemed to be lacking in cysts without microvilli. ATPase activity was not found in either type of structure. Finally, HT-29.18 differentiated cells expressed, at pH 9.0, a p-nitrophenylphosphatase activity six-fold greater than that of undifferentiated cells.
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PMID:Differential expression of alkaline phosphatase and ATPase activities in human colon carcinoma cell line HT-29.18 during differentiation. 296 Apr 4

Ubiquitin, a unique protein with esterase and carbonic anhydrase activity, has been found to have also a p-nitrophenyl phosphatase activity. This phosphomonoesterase activity of ubiquitin has an acidic pH optimum; its true substrate appears to be the phosphomonoanion, with a Km of 1.8 X 10(-3) M. It is competitively inhibited by the typical acid phosphatase inhibitors, arsenate (Ki = 1.3 X 10(-3) M), molybdate (Ki = 1.2 X 10(-6) M), and phosphate (Ki = 1.4 X 10(-3) M). These inhibitors have no effect on the CO2 hydration and p-nitrophenyl acetate esterase activities of the ubiquitin. Acetazolamide slightly inhibited the p-nitrophenyl phosphatase activity.
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PMID:The p-nitrophenyl phosphatase activity of ubiquitin from bovine erythrocytes. 299 74

The localization of oxidoreductases and transport enzymes in flask cells of the amphibian epidermis was studied at the light-microscopic level. In these cells, the deposition of cytochemical reaction products was very similar to that found in fish epidermal ionocytes, thus demonstrating histochemical similarities between these two types of cells. The present histochemical results revealed high levels of activity of alkaline phosphatase (ALPase), potassium-dependent nitrophenylphosphatase (K+-p-NPPase) and carbonic-anhydrase isozymes (CA-I and CA-II) in the apical region of the flask cells, indicating that enzyme zonation may be the main site of the ion pumping.
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PMID:Enzyme cytochemical and immunocytochemical studies of flask cells in the amphibian epidermis. 300 2

The common use of Na-K-ATPase as a marker enzyme for basolateral membranes in the kidney is based on the microscopic localization of the enzyme by the cytochemical assay of Na-K-ATPase as cysteine insensitive p-nitrophenylphosphatase (Ernst S.A., J. Cell Biol. 66, 586-606, 1975). Rat kidney cortex plasma membranes were therefore fractionated by differential pelleting in isotonic sucrose, followed by equilibrium banding in linear sucrose gradients, to compare the distribution of "biochemical" and "cytochemical" assayed Na-K-ATPase. In all fractions, the distribution of Na-K-stimulated Mg-dependent ATPase differed from the distribution of cysteine insensitive p-nitrophenylphosphatase (alkaline phosphatase). Evidence is presented that this difference is not only due to the separation of plasma membranes from different cell types, but simply reflects different membrane location of the enzymic activities.
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PMID:Analytical study on Na-K-ATPase (and cysteine insensitive p-nitrophenylphosphatase) in rat kidney-cortex microsomes subfractioned by zonal centrifugation. 301 34

Structural and functional properties of the small intestinal microvillus membrane were evaluated in the rabbit after administration of ethinyl estradiol, a synthetic estrogen with a demonstrated propensity to alter hepatic membrane lipid fluidity, and promote cholestasis. In the jejunum, no estrogen-induced changes in microvillus membrane total lipid, cholesterol or phospholipid content were observed. However, the ileal microvillus membrane in estradiol-treated animals demonstrates significant reductions vs. controls (per mg protein) in total lipid (0.55 milligrams vs. 0.89 milligrams) [corrected] and phospholipid (206.7 micrograms vs. 304.91 micrograms) (p less than 0.001) content, as well as modifications in specific phospholipid species. The increase in the ileal microvillus membrane cholesterol: phospholipid molar ratio (0.65 vs. 0.51, p less than 0.05) was associated with a significant decrease in membrane lipid fluidity reflected by an increase in fluorescence anisotropy measurements utilizing diphenyl hexatriene as the fluorophore (r at 25 degrees C = 0.306 vs. 0.282, p less than 0.05). Thermotropic lipid phase transitions, assessed by Arrhenius plots of both fluorescence data and ileal microvillus membrane p-nitrophenylphosphatase activity demonstrate that phase changes occur between and 24 and 28 degrees C in both treated and untreated groups. Within the temperature range studied (40-10 degrees C) no differences from control were observed in microvillus membrane alkaline phosphatase activity following estrogen treatment. These data therefore indicate that ethinyl estradiol-induced effects on microvillus membrane lipid composition and physical properties occur predominantly in the ileum and appear to be related, in part, to specific alterations in the availability of phospholipid following estrogen treatment.
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PMID:Effects of ethinyl estradiol on intestinal membrane structure and function in the rabbit. 301 19

Potassium-dependent p-nitrophenylphosphatase was demonstrated, using the lead citrate method of Mayahara et al. (1980), in frozen sections of calf intestine fixed in formalin-calcium. The calcium chloride included in the fixative was shown to improve the localization of the reaction markedly. The phosphatase activity observed in the basolateral cell borders of the surface epithelium in the small intestine and colon was reduced by 10 mM ouabain and by substitution of sodium ions for potassium ions, confirming that the reaction was representative for the second step in the Na+/K+-ATPase complex. The intensity of the basolateral enzyme reaction was in the order: colon greater than duodenum, proximal jejunum greater than ileum greater than middle and distal jejunum. The crypts reacted weakly. A reaction in the brush border of the proximal jejunum and duodenum and a granular reaction in the supranuclear cytoplasm of the epithelial cells was not influenced by ouabain. The staining pattern for the potassium-dependent phosphatase differed from that of alkaline phosphatase and Mg2+-dependent ATPase, which gave a reaction that was restricted to the brush border.
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PMID:Histochemical distribution of potassium-dependent p-nitrophenylphosphatase in the calf intestine. 302 61

A membrane fraction enriched in plasma membrane marker enzymes K+-dependent p-nitrophenyl phosphatase, 5'-nucleotidase and alkaline phosphatase was prepared from rat parotid glands using Percoll self-forming gradient. This fraction contained an ATP-dependent CA2+ transport system which was distinct from those located on the endoplasmic reticulum and mitochondria of parotid glands. The Km for ATP was 0.57 +/- 0.07 mM (n = 3). Nucleotides other than ATP such as ADP, AMP, GTP, CTP, UTP or ITP were unable to support significant Ca2+ uptake. ATP-dependent Ca2+ uptake displayed sigmoidal kinetics with respect to free Ca2+ concentration with a Hill coefficient of 2.02. The K0.5 for Ca2+ was 44 +/- 3.1 nM (n = 3) and the average Vmax was 13.5 +/- 1.1 nmol/min per mg of protein. The pH optimum was 7.2. Trifluorperazine inhibited Ca2+ transport with half maximal inhibition observed at 30.8 microM. Complete inhibition was observed at 70 microM trifluorperazine. Exogenous calmodulin however had no effect on the rate of transport. Na+ and K+ ions activated Ca2+ transport at 20 to 30 mM ion concentrations. Higher concentrations of Na+ or K+ were inhibitory.
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PMID:Characterisation of an ATP-dependent Ca2+ transport system in a plasma membrane enriched fraction from rat parotid. 345 46


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