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)

Alkaline phosphatase has been purified from cultured rat liver cells by butanol extraction, column chromatography on DEAE-cellulose and on Sephadex G-200, and preparative polyacrylamide gel electrophoresis. By electrophoresis on polyacrylamide, the purified enzyme was resolved into two active forms. Both forms have similar molecular weights of around 200,000. The subunit size was found to be 50,000 by SDS-polyacrylamide gel electrophoresis. These results suggest that alkaline phosphatase purified from cultured rat liver cells has a tetrameric structure. The optimum pH was found to be approximately 10.4, using p-nitrophenylphosphate as a substrate in a carbonate buffer system. The apparent Km was estimated to be 2.4 mM, using p-nitrophenylphosphate in carbonate buffer, pH 10.4.
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PMID:Purification and characterization of alkaline phosphatase in cultured rat liver cells. 2 75

An oral dose of 0.5 microgram of 1,25-dihydroxycholecalciferol (1,25-[OH]2D3) and 4 g of calcium carbonate was given daily to two dialysed patients and three undialysed patients in chronic renal failure with renal osteodystrophy. Treatment was given for 4-16 months. Intestinal calcium absorption became normal in all five patients. Plasma alkaline phosphatase, hydroxyproline, and immunoreactive parathyroid hormone were considerably reduced in all of the patients and in four of them these values were restored to normal. Bone histology was improved in all patients after treatment with 1,25-(OH)2D3. As well as a dramatic improvement in bone mineralisation, there was remodeling of trabecular architecture and a decrease in fibrosis in patients with initial parathyroid overactivity.
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PMID:Long-term effects of small doses of 1,25-dihydroxycholecalciferol in renal osteodystrophy. 7 68

This paper describes an Enzyme Linked Immunosorbent Assay (ELISA) for detecting IgG sensitized erythrocytes utilizing a commercially available anti-human IgG conjugated with alkaline phosphatase. Erythrocyte hemolysis in the assay was minimized by dissolving the p-nitrophenyl phosphate substrate in a carbonate-bicarbonate buffer. Nonspecific absorption of the enzyme conjugate to erythrocytes and glassware was reduced by adding 1% bovine serum albumin to wash solutions. Assay sensitivity was increased with greater concentrations of enzyme conjugate and erythrocytes in the incubation stage. The sensitivity of the described ELISA procedure is approximately equal to that of the standard antiglobulin test. Some possible future applications of ELISA in the blood bank are discussed.
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PMID:An enzyme linked immunosorbent assay (ELISA) for detecting IgG sensitized erythrocytes. 11 58

Differential centrifugation of rat small intestinal homogenates produced a crude brush border (BB) fraction that was enriched 15-fold for the marker enzymes, alkaline phosphatase and sucrase; contamination with mitochondrial enzymes, monoamine oxidase and succinate dehydrogenase, was minimal. ATP hydrolysis by this BB fraction was stimulated by addition of several anions to the incubation medium: HCO3 and Cl were equally effective in this regard, with NO3, NO2, SO4, and acetate being less stimulatory. SCN and CNO inhibited ATPase activity, whereas the divalent anion SO3 was stimulatory at low concentrations (less than 25 mM) but inhibitory at 100 mM. Maximum anion stimulation was observed at a Mg concentration of 0.5 mM, and pH optimum was 8.5. Kinetic analysis showed that HCO3 increased the Vmax without altering the Km for ATP; the Ka for this effect of HCO3 was 35 mM. This enzyme activity was completely inhibited by 20 mM L-phenylalanine, 10 mM L-cysteine, and 3 mM EDTA, compounds that also inhibited intestinal alkaline phosphatase. These results demonstrate the presence of anion-stimulated ATPase activity in rat small intestinal brush border and suggest that this activity may be related to intestinal alkaline phosphatase. The role of this enzyme in intestinal transport is not known, but could relate to the regulation of intestinal absorption and secretion.
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PMID:Anion-stimulated ATPase activity of brush border from rat small intestine. 15 3

The existence of a membrane-bound HCO3-stimulated ATPase in intestinal mucosa is controversial. A crude brush border fraction of rat small intestinal homogenates contained HCO3-ATPase activity which was inhibited by preincubation with 3 mM EDTA. Alkaline phosphatase activity of this preparation was also inhibited in a parallel, time-dependent fashion by preincubation with EDTA. When 5 mM ZnSO4 accompanied 3 mM EDTA in the preincubation mix, preservation of both enzyme activities occurred, demonstrating a requirement of Zn for the activity of both these phosphatases. These studies support the earlier contention that HCO3-ATPase and alkaline phosphatase activities may be different properties of the same enzyme, and raise the possibility that the ATPase could play a role in intestinal ion transport. The failure to identify a membrane-bound HCO3-ATPase by other workers could be due to the exposure of EDTA which occurred in their tissue preparation.
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PMID:Requirement of Zn to demonstrate HCO3-stimulated ATPase activity of rat small intestinal brush border. 15 7

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

A correlation was sought between changes in enzymes involved in gastric acid secretion (Mg-, NaK-, K- and HCO3-stimulated ATPases) and histological changes in gastric biopsies. Alkaline phosphatase was also studied. Mg- and NaK-stimulated ATPase activities increased significantly in biopsies from the pylorus and antrum which showed moderate or severe gastritis. NaK ATPase levels increased and HCO3 ATPase decreased in incisural, body and fundic mucosa which had intestinal metaplasia and atrophic gastritis. No K+ ATPase was found in normal mucosa. The total activity of alkaline phosphatase did not vary with histological changes in the gastric mucosa. Results indicate that the ATPase enzyme systems are sensitive indicators of gastric mucosal disease.
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PMID:Mucosal enzyme patterns in gastric epithelial disease. 21 78

Since dietary calcium had been reported to reduce plasma lipids, the effects of calcium carbonate (CaCO3, 2 g/day) and the calcium salt of p-chlorphenozyisobutyrate (Ca-CPIB, 2 g/day), both singly and in combination, were studied in outpatients with primary hyperlipidaemia. Three groups of five patients were followed in a double-blind cross-over study, in which placebo and the drugs were given alternately during four-week periods. The main results were: 1) CaCO3 alone did not produce any significant changes in plasma lipids. 2) Ca-CPIB reduced LDL-cholesterol in patients with type IIa and IIb by an average of 29 and 21%, respectively. It also lowered VLDL-triglyceride by 50% in type IIb and by 48% in four out of five patients with type IV. 3) The combination of CaCO3 and Ca-CPIB reduced LDL-cholesterol by 31 and 25% in types IIa and IIb, respectively. It also lowered VLDL-triglyceride by 48-52% in types IIa and by 46% in four out of five patients with type IIb. 4) Three out of five patients with type IV had a rise of LDL-cholesterol while on Ca-CPIB alone; two of the patients had the rise while on the combination. 5) After treatment with Ca-CPIB, either singly or in combination, there was a statistically significant lowering of ESR and of plasma inorganic phosphate and alkaline phosphatase. No clinical side effects were noted.
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PMID:Effect of calcium p-chlorphenoxyisobutyrate and calcium carbonate on plasma lipids and lipoproteins of patients with hyperlipoproteinaemia. 35 20

Two methods for measuring plasma alkaline phosphatase activity are compared: one makes use of phenyl phosphate, carbonate-bicarbonate buffer, and continuous-flow methodology; the other of p-nitrophenyl phosphate, diethanolamine buffer, and reaction-rate analysis. Results by the methods correlate well (r = 0.98) over a wide range of values (up to 10-fold the upper limit of normal). A factor can therefore be applied to convert results by one method into those that would be obtained by the other. The possibility that the presence of different proportions of isoenzymes in the plasma will affect this factor is considered. We have used the new method, with a conversion factor, as the routine method of alkaline phosphatase measurement in a clinical chemistry laboratory, with no problems.
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PMID:Plasma alkaline phosphatase assay: interconversion of results by two methods. 91 83

The factors which affect the standardisation and quality control of serum alkaline phosphatase assays are discussed. A quality control project was designed to test the performance of seven Birmingham laboratories in the assay of sera with alkaline phosphatase activities outside the range normally tested by the National Quality Control and Wellcome schemes. The results showed that the precision of individual laboratories was satisfactory. Differences between the results of the laboratories were considerable and could be accounted for by differences in methodology. Auto-Analyzer methods employing phenyl phosphate as substrate would best be standardised by adopting the optimised reaction conditions of Buch and Buch (1939); but the borate buffer of these authors should be replaced by the carbonate-bicarbonate buffer of Moss et al. (1971). To avoid the confusion which may arise in future if alkaline phosphatases are reported in U/l irrespective of the substrate, it is suggested that some substrate--indicative nomenclature may be advisable.
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PMID:Quality control of serum alkaline phosphatase assays: project report and discussion of some factors affecting the assay. 125 61


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