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)

The enzyme inorganic pyrophosphatase (PPiase, EC 3.6.1.1) from the odontoblastic layer of rat incisors has been studied by means of a radiochemical micromethod. The enzyme was incubated with 32P-pyrophosphate in tris-HCl buffer at 37 degrees C. The reaction was linear with time for at least 45 min, and the pH optimum was found to be 8.8, independent of the amount of pyrophosphate present. Heating the enzyme at 56 degrees C inhibited the enzyme activity rapidly, Mg2+ ions activated the enzyme by 15% at an ion concentration of 4 mM, while higher concentrations were inhibitory. Ca2+ ions and PO43-ions inhibited the enzyme at all concentrations. F- ions did not affect the PPiase at concentrations below 8 mM, whereas higher concentrations had an inhibiting effect. Urea was found to inhibit the enzyme at concentrations above 1.5 M, while EDTA was a strong inhibitor at very low concentrations. The characteristics of PPiase agree well with the properties of the enzyme nonspecific alkaline phosphatase (EC 3.1.3.1.) studied earlier.
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PMID:Determination of inorganic pyrophosphatase in rat odontoblast layer by a radiochemical method. 0 Jul 84

Cytologic, biochemical and immunoelectrophoretic studies were carried out of amniotic fluids in 100 ewes with normal pregnancy and 40 ewes that had miscarried. Each month of pregnancy a total of 20 and 8 animals of the two groups, respectively were studied. It was found that the biochemical and metabolic processes taking place in the fetus lead to changes in the amniotic fluids altering the pH value, the alkali reserve, the content of potassium, calcium, phosphorus, alkaline phosphatase as well as their bactericidal activity. More characteristic changes linked with pregnancy were observed in the cell composition of the amniotic fluids. With advancing in age the increase in cell count was accompanied (staining with Nile blue sulfate) with a rise of the "orange cell" content. The amniotic fluids of ewes with normal pregnancy were found to contain proteins which precipitated with hyper immune sera against blood serum and kidney, heart, and placenta proteins. In ewes that had miscarried the pH values of the amniotic fluids dropped in the months when abortions took place: 7.36, 7.11, 6.90, 6.80 and 6.90, as against 7.41, 7.36, 7.28, 7.17 and 7.18, respectively. Along with pH the alkali reserve also dropped to 37.9 in the first month and 14.20 in the fifth month. In ewes that had miscarried in the 2nd, 3rd, and 4th month these values were 18.90, 14.90, and 13.80 cu. cm, respectively. In cases of abortions the protein composition of the amniotic fluids showed higher levels of the alfa and beta globulins.
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PMID:[Study of the amniotic fluid of sheep in the normal course of pregnancy and in abortion]. 0 94

The presence of alkaline phosphatase (EC 3.1.3.1) activity has been demonstrated in nuclei of rat ventral prostate. This enzyme activity remained after washing of isolated nuclei with 0.5% Triton X-100; an acid phosphatase initially present with the nuclear fraction was removed by this treatment. The nuclear alkaline phosphatase, examined by utilizing p-nitrophenyl phosphate as substrate, had a pH optimum of 9.5-10.3, and a broad substrate specificity: p-nitrophenyl phosphate greater than phosphothreonine greater than beta-glycerophosphate greater than phosphoserine. The nuclear phosphatase was sensitive to denaturation by heat or urea treatments and was also inhibited by Pi, L-phenylalanine, homoarginine, dithiothreitol, and EDTA. The EDTA-inhibited enzyme was maximally reactivated by Zn2+, although Mg2+, or Ca2+ were also effective at somewhat higher concentrations. Orchiectomy of adult rats resulted in an increase in the nuclear alkaline phosphatase activity (2-3-fold at 24 or 48 h postorchiectomy). A decline in the protein: DNA ratio also occurred following orchiectomy, but the increase in phosphatase specific activity was evident whether expressed per unit of protein or per unit of DNA. Testosterone replacement following orchiectomy abolished the increase in nuclear phosphatase activity. The results suggest that the prostatic nuclear alkaline phosphatase may be involved in events related to inactivation of the prostate nucleus following androgen deprivation.
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PMID:Presence and androgen control of an alkaline phosphatase in the nucleus of rat ventral prostate. 0 31

The kinetic study of the C2+ ATPase activity of lymphocyte plasma memebranes allowed some properties of this enzyme to be evidenced. The Ca2+-activated hydrolysis of ATP is independent of a non-specific alkaline phosphatase. The substrate of the ATPase activity is the chelate Ca2+- ATP. Mg2+ may substitute for Ca2+ both as chelating ion and as activating ion. Several results suggest that we have only one ATPase, activated either by Ca2+-, or by Mg2+ with less efficiency; both chelates hve the same Km; pH values for maximum activity and transition temperatures are identical; the effects of free ions are also the same, activation at low concentration and inhibition at high concentration.
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PMID:[Kinetics of Ca 2+ or Mg 2+ activated ATPase from lymphocyte plasma membranes]. 0 56

In active odontoblasts from the rat incisor, used as a model system for biologic calcification, two distinguishable enzyme activities capable of degrading adenosine monophosphate (ATP) exist. Once can be inhibited ny 1-tetramisole, (+/-)-2,3,5,6,-tetrahydro-6-phenylimidazo (2.1B) THIAZOLE HYDROCHLORIDE (Levamisol) and (+/-)-6(m-bromophenyl)-5.6-dehydroimidazo (2.1-b) thiazole oxalate (R823) and is probably identical with nonspecific alkaline phosphatase (EC 3.1.3.1). The activity of the other enzyme, named Ca2+-ATPase, is dependent on the presence of Ca2+ or Mg2+ and is activated by these ions. The pH optimum of Ca2+-ATPase is 9.8. The Ca2+-ATPase is unaffected by Levamisole, R 8231, ouabain, ruthenium red, Na+ and K+ ions. Maximal activity was found against ATP, whereas adenosine diphosphate, guanosine triphosphate, inosine triphosphate and adensoine monophosphate were hydrolysed at lower rate. It may be speculated that the Ca2+-ATPase is concerned with the transmembranous transport of Ca2+ ions to the mineralization front.
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PMID:A comparison of ATP-degrading enzyme activities in rat incisor odontoblasts. 0 54

A brush border preparation from rat intestine was incubated with rat intrinsic factor-vitamin B12 complex in 0.01 M Tris-HCl buffer, pH 7.4. The 57Co-B12 uptake to brush borders was proportional to the amount of protein or to alkaline phosphatase activity in the preparations. The uptake increased with time of incubation. At 37degreesC, the uptake after incubation for 15 min was 80-85% of that for one hr. The uptake at 4degreesC was approximately 70% of that at 37degreesC. Ther was no difference as a result of adding glucose to the incubation medium. The uptake was observed in the alkaline environment above pH 6.3. Maximum uptake occurred at pH 8.0. Brush borders washed with Krebs-Ringer bicarbonate buffer (pH 7.4) exhibited no difference in B12 uptake, whether in the presence or absence of calcium ion. But brush borders washed with ethylenediaminetetraacetate exhibited no uptake when incubated in calcium-free medium. The uptake reached a maximum by addition of calcium ion at a concentration of 0.3 mM, and was not alter up to 10 mM. Addition of magnesium ion exhibited no uptake. Calcium-dependent B12 uptake was markedly inhibited by manganese ion. Magnesium ion seemed to slightly inhibit the calcium-dependent uptake.
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PMID:Effects of divalent cations on vitamin B12 adsorption to brush borders of rat intestine. 0 95

The effect of EDTA-decalcification, reactivating and activating procedures on the hydrolysis of ATP was studied histochemically in developing dental tissues in the rat. The incubation media contained lead citrate at alkaline pH and lead nitrate at neutral pH, and the results with ATP as substrate were compared with those obtained with beta-glycerophosphate. The ion dependency of ATP hydrolysis could only be ascertained in decalcified sections. As in earlier studies on the hydrolysis of beta-glycerophosphate in dental tissues, this hydrolysis could readily be reactivated through preincubation of the sections in a series of 0.1 M solutions of divalent cations; Zn2+ being the most efficient. This treatment was now found also to give rise to an ATP hydrolysis, which occurred without the need for activating ions in the incubation medium. This ATP hydrolysis should thus be described as nonspecific and, in terms of ion dependency, as due to a metalloenzyme, i.e. alkaline phosphatase. Activating ion dependent ATP hydrolysis in the dental tissues was found in the blood vessels and in the apical part of the secretory ameloblasts. The former was activated by Mg2+, Ca2+ and Mn2+, and the latter by Ca2+ and--almost specifically--by Sr2+. Preincubation with Zn2+ always inhibited the ion dependant ATP hydrolysis in the dental tissues.
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PMID:Adenosine triphosphate hydrolysis in rat dental tissues. A histochemical study of ion dependencies. 1 Nov 99

Some of the characteristics of the pyrophosphatase and ATPase activities studied in isolated cartilage matrix vesicles were found to be similar to those already reported for the solubilized and purified bone alkaline phosphatase. Thus, the pH optimum of the pyrophosphatase activity responded similarly to changes in the concentration of Mg2+, Ca2+, and PPi. Further, the ATPase activity was not activated by Ca2+ in the presence of an optimal Mg2+ concentration. It is proposed that a function of the alkaline phosphatase of matrix vesicles in vivo is to hydrolyze the substrates PPi, ADP, and ATP, which are known inhibitors of calcium phosphate precipitation.
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PMID:Pyrophosphatase and ATPase of isolated cartilage matrix vesicles. 1 78

1. On subcellular fractionation of rat brain homogenate, polyphosphoinositide phosphomonoesterase activity was greater in the cytosol than the membranous fractions. 2. The enzyme was purified from the cytosol by column chromatography on DEAE-cellulose, calcium phosphate gel and Sephadex G-100. 3. The final preparation of the enzyme showed a 430-fold purification over the whole homogenate and appeared to be homogeneous since it gave a single band on sodium dodecyl sulphate-polyacrylamide gel electrophoresis and on isoelectric focusing. The enzyme has a relatively low molecular weight and an isoelectric point of 6.8. 4. The phosphatase showed a high affinity for triphosphoinositide. Without added Mg2+, the Km was 25 muM and V was 33 mumol Pi released/min/mg protein. 5. The enzyme hydrolysed diphosphoinositide at a slower rate than triphosphoinositide. In the presence of 10 mM Mg2+, the Km values for triphosphoinositide and diphosphoinositide were 5 muM and 25 muM respectively and V was the same for each substrate. 6. Both Mg2+ and Ca2+ activated the enzyme. While Ca2+ produced maximum activation at 100 muM, a much higher concentration of Mg2+ (10 mM) was required to elicit comparable activation. The enzyme did not show an absolute requirement for Mg2+ or Ca2+ as it exhibited low activity in the presence of 0.5 mM EDTA or EGTA. 7. The phosphatase showed maximum activity between 7.4 and 7.6. A drop in pH to 7.0 activated it almost completely, whereas an increase in pH to 8.0 halved the activity. 7.0 activated it almost completely, whereas an increase in pH to 8.0 halved the activity.
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PMID:Purification and properties of polyphosphoinositide phosphomonoesterase from rat brain. 1 41

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


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