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)

Human placental microsomal 5'-nucleotidase (EC 3.1.3.5) was prepared free of alkaline phosphatase by isoelectric focusing. A total of seven electrophoretic variants were isolated during the preparation of six placentas. Only three to six variants were found in a single placenta. The isoelectric pH's were 6.70, 6.44, 6.23, 6.02, 5.76, 5.63 and 5.44. These were found to be composed of variable quantities of a large, medium and low molecular weight form. The apparent molecular weights of the medium and light form of the enzyme were 86 500 and 43 500, respectively, as estimated from Stokes radius and sedimentation velocity determinations. The electrophoretic variants were not distinguishable with respect to specific activity and Michaelis constants for AMP, GMP or CMP or inhibition by ATP, CTP or adenosine. These electrophoretic variants appeared to be pseudoisozymes based upon different states of aggregation of a common primary sequence. There was a wide range of substrate specificity among nucleoside 5'-monophosphates which included 2-deoxyribose compounds. With AMP as 100, substrate activity was: CMP, 122; NMN, 74; GMP, 68: IMP, 63; XMP, 28 and UDP-glucose, 68. The Michaelis constants for AMP, GMP and CMP ranged from 12-18 muM, from 33-67 muM and from 170-250 muM, respectively. Although 5'-nucleotidase was active in the absence of divalent cation, 5 mM MgCl2 stimulated the enzyme activity to 234% of control and shifted the pH optimum of 9.8 to a plateau from pH 7.4-9.8.
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PMID:Purine catabolism in man: characterization of placental microsomal 5'-nucleotidase. 0 35

A membrane fraction from calf thymocytes was used to investigate molecular and catalytic properties of membrane-bound alkaline phosphatase (ortho-phosphoric-monoester phosphohydrolase EC 3.1.3.1). The principal findings were: 1. Solubilization of membranes with the non-ionic detergent Triton X-100 increases alkaline phosphatase activity by 30-40%. The enzyme activity elutes in a single peak (Stokes' radius = 7.7 nm) after chromatography in Sepharose 6B in the presence of Triton X-100. The activity also sediments as a single component of approx. 6.4 S during centrifugation in sucrose gradients containing Triton X-100. 2. Ion-exchange chromatography and isoelectric focusing in the presence of Triton X-100 indicate substantial charge heterogeneity. Two overlapping bands, a peak at pH 5.92 with a pronounced shoulder at pH 5.29, are apparent by isoelectric focusing. 3. The pH optimum for hydrolysis of p-nitrophenylphosphate (pNPhP) by the undissolved enzyme(s) is 9.57. Half-maximal activity occurs at pH 8.65 and ph 10.45. Triton X-100 has no effect on the pH profile. 4. Catalytic activity is affected by amines, especially analogues of ethanolamine. Diethanolamine exerts a unique stimulatory effect, but does not change the pH dependency. Increasing the concentration of diethanolamine from 0 to 1 M causes a 6-fold increase in Km and a 10-fold increase in the rate of hydrolysis of pNPhP. Glycine is inhibitory. 5. EDTA causes an irreversible loss of activity with t1/2 (1 mM EDTA, pH 8.2, 23 degrees C) = 3.5 h. Optimal activity is achieved in 0.1--1.0 mM Mg2+, although this does not cause the degree of activation reported to occur with the purified enzymes. Other divalent ions are inhibitory. Concentrations required to reduce activity to 50% of control are: Zn2+, 4.0 muM (no added Mg2+) and 30 muM (in the presence of 1 mM Mg2+); Mn2+, 0.25 mM (+/- Mg2+); Ca2+, 20 mM (+/- Mg2+). 6. Monovalent cations have little effect on activity. In the absence of added Mg2+, 50--150 mM Na+ is partially inhibitory, but markedly less so in the presence of 1 mM Mg2+. K+ has no significant effect. 7. Of the substrates tested, pNPhP (Km = 44 muM) was most rapidly hydrolyzed. Other substrates (rate relative to pNPhP) were alpha-naphthylphosphate (0.79), 2'-AMP (0.80), 5'-AMP (0.70), 3'-AMP (0.63), alpha-glycerophosphate (0.47) and glucose 6-phosphate (0.35). Phosphodiesterase activity was less than or equal to 10% of the phosphomonoesterase activity (for pNPhP) as evidenced by the lack of hydrolysis of bis(p-nitrophenyl)-phosphate and cyclic 3',5'-AMP. The ability of these substances to inhibit hydrolysis of pNPhP reflected their capacity as substrates, i.e. the most inhibitory were the most rapidly hydrolyzed.
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PMID:Calf thymus alkaline phosphatase. I. Properties of the membrane-bound enzyme. 1 42

A repressible alkaline phosphatase has been isolated from the extreme bacterial thermophile. Thermus aquaticus, and has been purified to homogeneity as judged by disc acrylamide electrophoresis and sodium dodecyl sulfate electrophoresis. Upon investigation, the purified enzyme was shown to hydrolyze certain phosphodiesters in addition to a wide variety of phosphomonoesters. The diesters included bis-p-nitro-phenyl phosphate and thymidine 3'-monophospho-p-nitro-phenyl ester. The temperature optimum for the diesterase activity was 80--85 degrees at pH 7.2. Orthophosphate competitively inhibited both activities. Nucleotides such as AMP, ADP, and ATP also inhibited both esterase activities as did alpha-D-glucose 1-phosphate and alpha-sodium glycerol phosphate. The isoelectric point of the enzyme was determined to be 8.4.
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PMID:Repressible alkaline phosphatase from Thermus aquaticus: associated phosphodiesterase activity. 1

Purified chondrocytic alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) from bovine fetal epiphyseal cartilage hydrolyzes a variety of phosphate esters as well as ATP and inorganic pyrophosphate. Optimal activities for p-nitrophenyl phosphate, ATP and inorganic pyrophosphate are found at pH 10.5, 10.0 and 8.5, respectively. The latter two substrates exhibit substrate inhibition at high concentrations. p-Nitrophenyl phosphate demonstrates decreasing pH optima with decreasng substrate concentration. Heat inactivation studies indicate that both phosphorolytic and pyrophosphorolytic cleavage occur at the same site on the enzyme. Mg2+ (0.1-10.0 mM) and Mn2+ (0.01-0.1 mM) show a small stimulation of p-nitrophenyl phosphate-splitting activity at pH 10.5. Levamisole, Pi, CN-, Zn2+ and L-phenylalanine are all reversible inhibitors of the phosphomonoesterase activity. Pi is a competitive inhibitor with a Ki of 10.0 mM. Levamisole and Zn2+ are potent non-competitive inhibitors with inhibition constants of 0.05 and 0.04 mM, respectively. The chondrocytic alkaline phosphatase is inhibited irreversibly by Be2+, EDTA, EGTA, ethane-1-hydroxydiphosphonate, dichloromethane diphosphonate, L-cysteine, phenyl-methylsulfonyl fluoride, N-ethylmaleimide and iodoacetamide. NaCL, KCL and Na2SO4 at 0.5-1.0 M inhibit the enzyme. At pH 8.5, the cleavage of inorganic pyrophosphate (pyrophosphate phosphohydrolase, EC 3.6.1.1) by the chondrocytic enzyme is slightly enhanced by low levels of Mg2+ and depressed by concentrations higher than 1mM. Ca2+ show only inhibition. Similar effects of Mg2+ and Ca2+ on the associated ATPase (ATP phosphohydrolase, EC 3.1.6.3) activity were observed. Arrhenius studies using p-nitrophenyl phosphate and AMP as substrates have accounted for the ten-fold difference in V in terms of small differences in both the enthalpies and entropies of activation which are 700 cal/mol and 2.3 cal/degree per mol, respectively.
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PMID:Enzymatic characterization of the chondrocytic alkaline phosphatase isolated from bovine fetal epiphyseal cartilage. 4 Jun 3

The three xanthine derivatives, caffeine, theophylline and 3-isobutyl-1-methyl-xanthine (IBMX) produced dose-dependent increases in cyclic AMP concentrations in HeLa cells after long term treatment. Only IBMX produced increases over the first 60 minutes, with a peak of approximately 5-fold control values five to 10 minutes after the addition of the drug. About four hours after the addition of either 0.67 or 1.0 mM IBMX there was a second peak in the concentration of cyclic AMP which was at least as large and usually larger than the peak observed at five to ten minutes. Neither caffeine nor theophylline increased cyclic AMP concentrations above control values until one hour after addition of the compounds, and there was no indication of a peak in the concentration at four hours. Between 24 and 72 hours, all three compounds produced elevations in cyclic AMP levels that were steadily maintained. At any given concentration, the order of potency was IBMX greater than theophylline greater than caffeine. If the xanthine derivatives were removed from the medium after 24 hours of treatment, the cyclic AMP concentrations fell to control levels within one hour. Treatment with 5-iodo-2'-deoxyuridine (IdUrd) or hydrocortisone alone did not change the levels of cyclic AMP, nor did the presence of these inducers of alkaline phosphatase activity alter the effects of the xanthine derivations on cyclic AMP concentrations. The data showed a significant correlation between the magnitude of the increase in cycli AMP concentrations over the period from 24 to 72 hours and the degree of inhibition by the xanthine derivatives of the induction of alkaline phosphatase activity.
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PMID:The inhibition by xanthine phosphodiesterase inhibitors of the induction of alkaline phosphatase activity in HeLa cells: relationship of enzyme activity to cyclic AMP concentrations. 9 Jun 81

Human adult lung fragments removed from macroscopically undamaged and anthracosis exempted zones of lungs of 20 pneumonectomies made for cancer, were tested for 25 enzymic activities. The location and intensities of these enzymic activities were different in the lung tissue components; The bronchial epithelia contained highly active LDH, MDH, SDH, NADH-TR and NADPH-TR, glucose-6-phosphate dehydrogenase, active hydroxyproline-2-epimerase, alkaline phosphatase. Ca2+-activated ATP-ase, and beta-galactosidase. Bronchial and vascular muscles presented intense activities of LDH, MDH and SDH of alkalinephosphatase, AMP-ase and Ca2+-activated ATP-ase, as well as of beta-galactosidase. The alveolar walls presented high activities of SDH, MDH and LDH, of alkaline and acid phosphatases, of beta-galactosidase and of Tween-40 and 60-esterases, of HEP, cytochrome-oxidase and peroxidase. The free alveolar macrophages were active for LDH, MDH, SDH, NADH-TR and NADPH-TR, G1-6-ph-DH, acid and alkaline phosphatase, cytochrome-oxidase and peroxidase, HEP, AMP-ase and Mg2+-activated ATP-ase, Tween-esterases, naphthol-ASD-acetate esterase, and beta-galactosidase. The endothelia contained high activities of alkaline phosphatase, of AMP-ase and Mg2+-activated ATPase, of LDH, MDH and SDH, and of beta-galactosidase. In bronchial lymphoid nodules it was the LDH, MDH, SDH, cytochrome-oxidase and peroxidase, HEP, alkaline phosphatase and AMP-ase, Tween-60-esterase and beta-galactosidase that were active. The interlobular areas of the lung presented intense activities of SDH, MDH, LDH, HEP and cytochrome-oxidase. The activities of the other tested enzymes were weaker or absent in the adult human lung components, the same as those of aminopeptidases which were present only in some free alveolar macrophages. The discussion of some relationships between these enzymic actitivies and the morphology of the human adult lung tissue asserted that the latter could not be considered as a "normal" tissue but as one overstrained by the components of blood and polluted air.
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PMID:Histoenzymology of the lung. I. Enzyme activities of the lung tissue of acult humans; relationships between structure and functions. 14 Mar 14

The disruption of the molecular organization of the plasma membrane of leukocytes by phagocytosable particles, or by agents such as surfactants, antibodies, phospholipase C, fatty acids and chemotactic factors, leads to a stimulation of the phagocyte oxidative metabolism. Concanavalin A (Con A) has been used as a tool to study the mechanism of this metabolic regulation. The binding of Con A to the surface of polymorphonuclear leukocytes (PMNL) or macrophages produces a rapid enhancement of oxygen uptake and glucose oxidation through the hexose monophosphate pathway (HMP). This is explained by an activation of the granular NADPH oxidase, the key enzyme in the metabolic stimulation. The effect of Con A is not due to endocytosed lectin, since Con A covalently coupled to large sepharose beads still acts as stimulant. The metabolic changes caused by Con A are reversible. If, after the onset of stimulation, sugars with high affinity for Con A are added to the leukocyte suspension, the activity of granular NADPH oxidase and the rate of respiration and glucose oxidation return to their resting values. The metabolic burst, while partially supressed by treatment of PMNL with iodoacetate, sodium flouride and cytochalasin B, is slightly increased by colchicine. Con A induces a selective release of granular enzymes (beta-glucuronidase, peroxidase, alkaline phosphatase) from PMNL, whereas no leakage of cytoplasmic enzymes is observed. The enzyme release is inhibited by iodoacetate and by drugs known to increase cell levels of cyclic AMP. Based on a current view of the mode of interaction between Con A and cell surfaces, a model of the metabolic disruption of leukocytes is presented.
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PMID:Concanavalin A as a probe for studying the mechanism of metabolic stimulation of leukocytes. 16 45

In ten patients with Paget's disease of bone (Group I) intramuscular injection of 50 MRC units of synthetic Salmon calcitonin (SCT) induced a marked decrease of serum calcium (-1,444 mg%), serum phosphorus (-1,06 mg%), urinary total hydroxyproline (-71%), and a marked increase of urinary cyclic AMP (+ 114%). These changes occur at maximum 6 hours after the injection with a return to the initial values after 24 hours. In six other patients with Paget's disease (Group II) the acute biological effects were of the same nature and magnitude after the injection of 100 MRC units of SCT. In this group a significant but temporary increase of the plasma parathyroid hormone level was demonstrated. The magnitude of the hypocalcemia seems proportional to the initial serum alkaline phosphatase and urinary hydroxyproline levels. After one month of treatment, the alkaline phosphatase and urinary hydroxyproline have more marked and more regular decrease in group II who received 100 MRC units of SCT daily than in group I who received 50 MRC units three times a week. The cellular mechanisms of these biological changes are discussed. A posology of two daily injections of 50 MRC units of SCT is suggested when a quick and maximum stoppage of pagetic remodeling is required.
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PMID:[Short-term biological effects of synthetic salmon calcitonin in Paget's disease. Influence of posology]. 17 38

The P4 variant of Dictyostelium discoideum is characterized by the production of fruiting structures in which the overall proportion of stalk to spore material is increased, relative to the wild type. The altered morphology of the mutant is due to increased sensitivity to cyclic AMP which promotes stalk cell differentiation. In the presence of 10-4 M-cyclic AMP the entire population of P4 amoebae forms clumps of stalk cells on the surface of the dialysis membrane support. Measurement of changes in activity of a range of developmentally-regulated enzymes during the development of P4 in the presence and absence of cyclic AMP has allowed us to identify three classes of enzyme: (i) Those, such as beta-glucosidase II, trehalose-6-phosphate synthetase and uridine diphosphogalactose-4-epimerase, which are required for the production of spores. (ii) Enzymes, primarily but perhaps not exclusively, required during stalk cell formation. Typical of these are N-acetylglucosaminidase and alkaline phosphatase. (iii) General enzymes, such as threonine dehydrase, alpha-mannosidase and uridine diphosphoglucose pyrophyosphorylase, which are present inboth pre-stalk and pre-spore cells and appear to be necessary for the development of both cell types.
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PMID:Enzyme activity changes during cyclic AMP-induced stalk cell differentiation in P4, a variant of Dictyostelium discoideum. 17 91

Cholera enterotoxin, 45 mug per 250 g body weight, administered intravenously to rats, caused a 6-fold rise in the activity of liver alkaline phosphatase in 12 hr. There was no change in bile volume or in the concentration or total bile content of Na+, K+, HCO3-, or Cl- for 36 hr after the administration of cholera toxin. However, bile phospholipid output fell markedly from a control level of 15.0 +/- 1.0 mumol per 6 hr to a low level of 4.0 +/- 1.2 mumol per 6 hr in the 12- to 18-hr collection, P less than 0.001. There was a similar fall in bile acid secretion, from a control value of 9.8 +/- 0.4 mumol per 6 hr to 4.1 +/- 0.9 mumol in the 12- to 18-hr period, P less than 0.01. The cholera effect was prolonged. Bile acid and phospholipid secretion rates did not return to control values until 30 to 36 hr after the administration of cholera enterotoxin. The cholera toxin-induced reductions in bile acid and phospholipid secretion into bile did not appear to be mediated by adenyl cyclase or cyclic AMP because neither glucagon, a known stimulator of liver adenyl cyclase, nor dibutyryl cyclic AMP had any effect on the secretion into bile of bile acids or phospholipid. The administration of cholera toxin was not associated with any increase in the secretion of free choline into bile. Glucagon and dibutyryl cyclic AMP, two other substances known to increase the activity of rat liver alkaline phosphatase, also had no stimulatory effect on the secretion of free choline into bile. The results do not support the hypothesis that the main function of rat liver alkaline phosphatase is to facilitate the excretion of free choline into bile.
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PMID:Effects of cholera enterotoxin, glucagon, and dibutyryl cyclic AMP on rat liver alkaline phosphatase, bile flow, and bile composition. 17 82


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