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

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 inorganic pyrophosphatase (PPiase) activity was determined by a colorimetric method in the odontoblasts and the parts of the enamel organ related to enamel matrix formation and enamel maturation. The effects on PPi hydrolysis by EDTA, R 8231, urea and heat treatment were found to be almost identical to those reported for nonspecific alkaline phosphatase (APase) in the same tissues. The Mg2+ activation curve for PPiase was also similar. Like those of APase, these characteristics of PPiase activity were identical in the three locations studied. It is suggested that the close similarity in the properties of PPiase and APase is due to activity of the same enzyme, a concept which is in agreement with recent biochemical and histochemical studies of calcification.
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PMID:Inorganic pyrophosphatase in isolated enamel organ and odontoblasts from the rat incisor. 0 71

Sixty-one patients with elevated alkaline phosphatase activity due to liver or bone diseases were studied. An attempt was made to identify the origin of the increased alkaline phosphatase by chemical inhibition, by inactivation by heat and urea, and by electrophoretic separation. The results obtained from these procedures were correlated with the gamma-glutamyl transpeptidase activities performed on each patient. We concluded from this study that gamma-glutamyl transpeptidase determination, together with alkaline phosphatase electrophoretic separations, are useful laboratory procedures for accurately identifying the origin of elevated alkaline phosphatase activity.
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PMID:The use of gamma-glutamyl transpeptidase in differentiating liver from bone isoenzymes of alkaline phosphatase. 1 91

Twelve male duodenal ulcer in-patients received in a double-blind trial either the histamine H2-receptor antagonist cimetidine (4 X 200 mg/d p.o.) or placebo capsules. Ulcer sizes were assessed endoscopically before therapy followed by repeat endoscopy at weekly intervals. Duodenal ulcer healing was significantly more rapid in cimetidine-treated patients than in those receiving the placebo (chi2 test; P less than 0.0005). Plotting of log ulcer sizes (mm2) against time (days) resulted in regression lines the slopes of which indicated the respective half-time of ulcer healing: about 6 days on cimetidine therapy and about 20 days on placebo treatment. Gastric secretion of acid, protein, pepsin, and N-acetylneuraminic acid-containing glycoproteins was not altered by a 4-week course of daily cimetidine or placebo, nor pancreatic secretion of bicarbonate and enzymes. No statistically significant changes in laboratory findings (haemoglobin, white blood-cells, neutrophils, platelets, alkaline phosphatase, blood-urea, serum-creatinine, GOT, GPT) were associated with treatment.
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PMID:[Effective treatment of duodenal ulcer with cimetidine (author's transl)]. 1 Oct 86

The enzyme alkaline phosphatase (AP) (EC 3.1.3.1) in three different calcification areas was studied by means of a spectrophotometric micro method using p-nitrophenylphosphate as a substrate. Rat maxillary incisor odontoblasts and enamel organ from the zones of matrix formation and maturation and tissue from rabbit metatarsal cartilage were allowed to react with the substrate in glycine-NaOH buffer at room temperature. The reaction was found to be linear for a minimum of 20 min. The pH optima for AP from these tissues were in the pH range of 10.0-10.3. In order to compare AP from the four calcification areas different parameters were studied. Heating at 56 degrees C or 60 degrees C for varying times revealed that the enzymes were almost completely inactivated after 10 min. Mg2+ ions activated the enzymes by about 25% at concentrations of 2.5 mM (enamel organ 1.25 mM); while only higher concentrations of Mg2+ had an inactivating effect, Ca2+ and PO3-4 ions were inactivating at varying concentrations. F- ions showed no effect on AP activity at concentrations below 250 mM (enamel organ 125 mM) but caused inactivation of the enzymes at about 50% at 1 M. EDTA was found to be a very effective AP inactivator at concentrations above 0.06 mM, whereas urea did not noticeably affect the enzyme reactions at concentrations below 1 M. At higher concentrations, inactivation was observed. In order to determine AP localization in the epiphyseal plate successive 40-mum-thick, freeze-sectioned slices were analyzed. The activity was highest nearest the zone of cartilage calcification and decreased towards the reserve cell zone. It was concluded that the same AP isoenzyme is present in these quite different calcification loci.
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PMID:A comparative study of alkaline phosphatase in calcifying cartilage, odontoblasts and the enamel organ. 1 71

The ATP-splitting enzyme activity in odontoblasts isolated from rat incisors has been studied by means of a radiochemical and a colorimetric micromethod. The results with the two methods were virtually identical. The reaction was linear with time for at least 45 min. The pH optimum was found to be 9.8 independently of the ATP concentration. Maximal substrate saturation occurred at a total ATP concentration of 3 mM. Ca2+ and Mg2+ ions activated ATP degradation. F-ions did not affect the activity at low concentrations, whereas higher concentrations were inhibitory. Na+ and ions were slightly inhibitory. Urea inhibited the enzyme activity at concentrations above 1.5 M, while EDTA and EGTA were strong inhibitors at very low concentrations. When incubating in the presence of low concentrations of specific inhibitors for nonspecific alkaline phosphatase, levamisole and R8231, about 20% ATP degrading enzyme activity remained. In conclusion it is suggested that there are at least two ATP degrading phosphatases active at alkaline pH.
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PMID:ATP-ase activity in the odontoblastic layer of rat incisor. Determination with a radiochemical and a colorimetric method. 1 93

The interaction of human organ alkaline phosphatases (orthophosphoric-monoester phosphohydrolases (alkaline optimum), EC 3.1.3.1) with sugars was studied. Hexosamines, N-acetylneuraminic acid (NANA or sialic acid), N-acetylmuramic acid and N-acetylglycolylneuraminic acid inhibited human organ alkaline phosphatase activities. Of these, sialic acid was the most effective inhibitor. The pH profiles for the enzymes in the absence and presence of sialic acid were similar. The sialic acid - enzyme complex was more heat stable than the free enzyme between 20 and 45 degrees C. Lineweaver-Burk plots of 1/v versus 1/S at various concentrations of sialic acid showed intersecting straight lines indicating that the mechanism of inhibition was a mixed type. The Ki value obtained from the plots of 1/v versus the square of sialic acid concentration was 0.07 mM for the hepatic, sialidase-treated hepatic, and intestinal alkaline phosphatases. The respective Hill coefficients varied somewhat with the alkaline phosphatase isoenzyme. Hyperbolic curves were obtained when the percentage of remaining activity was plotted against the substrate concentration at different concentrations of sialic acid. The Hill coefficient was lowered in the presence of sialic acid. The sialidase-treated hepatic enzymes used gave the most effective conversion. Partial denaturation of the enzyme with urea, or pronase digestion had a little if any effect on the sialic acid inhibition with constant time.
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PMID:Inhibition of alkaline phosphatase by sialic acid. 1 56

1. Alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) in guinea pig thymus was extracted optimally in 10 mM Tris - HCl buffer at pH 8.0 containing 5 g/l Triton X-100. 2. alpha-Glycerophosphate, beta-glycerophosphate and phenolphthalein monophosphate were hydrolyzed by thymus extract with a pH optimum at 9.8-10.0, whereas p-nitrophenylphosphate and alpha-naphthylphosphate were hydrolyzed with pH optima at 10.7-10.8 and beta-naphthylphosphate at pH 11.2. P-Nitrophenylphosphate and phenolphthalein monophosphate proved to be the most suitable substrates. 3. Alkaline phosphatase was effectively inhibited by EDTA, Zn2+, histidine and urea therefore resembling the inhibition characteristics of alkaline phosphatase in the placenta and kidney, but not that in the liver and intestine, which differed markedly. 4. DEAE-cellulose chromatography and polyacrylamide disc electrophoresis revealed three enzyme peaks which did not differ in their substrate specificities and modifier characteristics. 5. Polyacrylamide disc electrophoresis of thymus, serum, placenta, kidney, liver, bone and intestine revealed no alkaline phosphatase bands definitely unique to thymus.
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PMID:Biochemical characterization of alkaline phosphatase in guinea pig thymus. 1 86

1. We report on the clinical usefulness of alkaline phosphatase isoenzyme determinations using a combined chemical inhibition method on 731 patient serum specimens exhibiting elevated (greater than 350 U/L) alkaline phosphatase (AP) activity. 2. The relative percentages of the organ-specific alkaline phosphatase activities were computed on the basis of three independent assays: total activity, activity in the presence of 10 mMl-phenylalanine, and activity in the presence of 3.1 M urea. 3. Gamma-glutamyl transferase (GGT) activity assays were also performed on the same specimens. Using an upper reference limit of 30 U/L for GGT and comparing the GGT results with the percent liver AP, we found that the GGT results were 91% sensitive and 60% specific. 4. We conclude that AP isoenzyme determinations are very useful in identifying the organ source(s) responsible for elevated AP values. 5. The reference ranges for several age groups in relation to the adult population and their significance are presented.
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PMID:Clinical usefulness of alkaline phosphatase isoenzyme determinations. 2 Oct 38


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