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)

Aromatic residues of bovine kidney alkaline phosphatase appear to be involved in the interaction with ascorbate, as shown by the strong quenching of intrinsic fluorescence and absorption. Difference u.v.-absorption spectra clearly indicate that conformational changes also occur. The pH value at which the greatest fluorescence deactivation is found is close to that necessary for optimal catalytic activity and for maximal inhibition by ascorbate. A protective effect against ascorbate is afforded by Pi. Time profiles of inactivation on one side and of absorbance and emission quenching on the other display opposite behaviours. Attempts to reverse the effects by the use of KOH fail to restore enzyme activity or to modify the spectral effects of ascorbate. The protein alterations are related, directly or indirectly, to the enzyme active centre and can be probably ascribed to the redox and chelating properties of ascorbate.
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PMID:The relationship between the optical properties and the kinetic behaviour of ascorbate-inhibited alkaline phosphatase. 382 59

Different water purity provokes a great variation of the stability of ascorbic acid and isoascorbic acid solutions. The effect of temperature on ascorbate aerobic oxidation was assessed by means of Arrhenius plots from which thermodynamic parameters were derived. The presence of bovine serum albumin drastically reduces the vitamin oxidation rate regardless of stereoisomerism. On the other hand the interaction with alkaline phosphatase, an enzyme inhibited by preincubation with vitamin C, does not modify significantly the stability in the experimental conditions used.
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PMID:Ascorbic acid stability in aqueous solutions. 409 Nov 46

Gamma-linolenic acid has been shown to suppress the rate of proliferation of a number of malignant cell lines in culture. To test the proposal that this was a specific prostaglandin 1- or 2-series effect, 379 batches of MG63 human osteogenic sarcoma cells were seeded in Greiner flasks and cultured in media supplemented with a range of unsaturated fatty acids and prostaglandins. The monounsaturated fatty acid oleic acid enhanced the rate of cancer cell proliferation. The polyunsaturated fatty acids linoleic acid, gamma-linolenic acid, arachidonic acid, alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid, as well as prostaglandins E1 and A1 suppressed the rate of cell proliferation. Total suppression of colony forming and cell proliferation occurred at high levels of polyunsaturated fatty acid supplementation. In addition gamma-linolenic in the form of evening primrose seed oil and vitamin C has been given to 6 patients with histologically diagnosed primary liver cell cancer. Some clinical improvement and reduction in tumor size occurred in 3 cases. One patient has shown remarkable improvement in reduction of liver and tumor size on the CAT scan and reduction of the serum alkaline phosphatase from 2830 to 295 units and gamma-glutamyl transaminase from 274 to 82 units. Thus preliminary clinical results suggest that gamma-linolenic acid may be effective in the management of human cancer patients and further trials should be conducted. However, the cell culture results suggest that although the essential fatty acids suppress proliferation, eicosanoids of all 3 series may be involved. The proliferation suppressive effect of docosahexaenoic acid suggests that other aspects than only eicosanoid activity may also be important in the suppression of cancer cell proliferation.
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PMID:Some effects of the essential fatty acids linoleic acid and alpha-linolenic acid and of their metabolites gamma-linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and of prostaglandins A1 and E1 on the proliferation of human osteogenic sarcoma cells in culture. 608 35

Cultures of osteoblastlike cells obtained from the endosteal surfaces of rabbit long bones formed and mineralized an extracellular matrix when they were supplied daily with medium containing fresh ascorbate. No matrix formed without this supplementation. The matrix mineralized whether or not beta-glycerophosphate, a substrate of alkaline phosphatase, was added to the medium. The ion-transporting ATPase activities of untreated, ascorbate-treated, and ascorbate plus beta-glycerophosphate-treated cells were measured. Ascorbate-treated and ascorbate plus beta-glycerophosphate-treated cells had similar enzyme activities. The activities of the Ca2+-ATPase; Ca2+,Mg2+-ATPase; and alkaline phosphatase in treated cells were elevated over the activities in untreated cells. Na+,K+-ATPase activity was lower in treated than in untreated cells. HCO3--ATPase activity was not changed by treatment. Alkaline phosphatase activity was 20 times higher in freshly isolated osteoblastlike cells than in cells grown to confluence in primary culture. In addition, subculturing further reduced the activity of this osteoblast-marker enzyme. The activities of the ion-transporting ATPases and alkaline phosphatase in second passage cells were similar to the activities of these enzymes in fresh, noncalcifying tissues. Nevertheless, second passage cells retain the ability to mineralize an extracellular matrix, and their ion-transporting ATPase and alkaline phosphatase activities are altered when the cells mineralize a matrix.
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PMID:Ion-transporting ATPases and matrix mineralization in cultured osteoblastlike cells. 609 28

The effect of vitamin C deficiency on various enzymes of the intestinal epithelium has been studied in guinea pigs. Brush border sucrase and alkaline phosphatase activities were considerably enhanced (p less than 0.001), but leucine aminopeptidase levels were reduced in scorbutic animals compared to the control group. There was essentially no change in the activity of maltase under these conditions. Kinetic studies with sucrase and alkaline phosphatase in control and scorbutic animals revealed that augmentation of the enzyme activities in scurvy is due to enhanced enzyme contents. Lactate dehydrogenase, succinate dehydrogenase, glucose-6-phosphatase and Mg+2 ATPase also exhibited reduced activities in the intestine of vitamin-C-deficient animals. Observed alterations in the activities of intestinal enzymes in scurvy were restored to control levels upon feeding of vitamin C to scorbutic guinea pigs.
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PMID:Alterations in the activities of intestinal enzymes in vitamin-C-deficient guinea pigs. 627 90

Guinea pigs well supplied with vitamin C show a linear relation between serum alkaline phosphatase activity and body weight. Investigations in guinea pigs induced to low ascorbic-acid levels by two different procedures (complete and partial deprivation of vitamin C) demonstrated that the activity of the alkaline phosphatase is not generally decreased in the serum of ascorbic-acid-deficient guinea pigs. Decreases of the serum enzyme levels reported in guinea pigs completely deprived of vitamin C, i.e. in acute deficiency, may be due to stress factors.
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PMID:Activity of alkaline phosphatase in the serum of normal and ascorbic-acid-deficient guinea pigs. 707 77

The effect of vitamin C deficiency on the digestive and absorptive functions of the gut has been investigated in guinea pigs. The absorption of D-glucose was significantly elevated, but that of L-leucine, L-alanine and L-lysine considerably depressed in the intestine of scorbutic guinea pigs compared to controls. The intestinal transport of vitamin B12 was also diminished. Activities of sucrase and alkaline phosphatase on the brush border were enhanced, but that of leucine aminopeptidase markedly reduced in scorbutic animals compared to controls. Maltase activity was unaffected in vitamin C deficient animals. Chemical analysis of the brush borders isolated from scorbutic animals revealed a considerable decrease in membrane protein, total lipids, phospholipids, and free cholesterol contents compared to control animals. In vivo 2-(14)C-acetate incorporation into membrane lipids suggested that the observed decrease in lipid components of the scorbutic membranes is due to reduced synthesis. Administration of ascorbic acid to scorbutic animals ameliorated the intestinal aberrations observed in scurvy.
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PMID:Effect of vitamin C deficiency in guinea pigs on intestinal functions and chemical composition of brush border membrane. 730 86

The influence of extraneous supplementation of L-ascorbic acid in chronic chlordane toxicity has been studied in rats. Oral administration of chlordane brings about a marked growth retardative effect, stimulates vitamin C synthesis in the system, elevates the vitamin C status of the liver and kidney tissues and also the urinary excretion. It inhibits the activities of acid and alkaline phosphatases, SDH and Mg2+-ATPase of both hepatic and renal tissues. The activities of serum and mitochondrial GOT, serum alkaline phosphatase, and glucose-6-phosphatase of both hepatic and renal tissues are markedly stimulated. The normal histological patterns of both liver and kidney tissues are grossly altered under chlordane toxicity condition. There occurs marked increase in the hepatic lipid composition. Supplementation of L-ascorbic acid in high doses to the chlordane treated rats can effectively counteract some of these alterations in respect of enzyme activities, morphological characteristics and of hepatic lipid composition.
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PMID:Studies on the protective effects of L-ascorbic acid in chronic chlordane toxicity. 731 25

The effects of race, age, and sex on selected blood components for 429 black and white adults over 34 year in southwest Mississippi were studied. Fasting blood was collected early in the morning. Whole blood was used for the determination of hematocrit and hemoglobin. The sera were used for the analysis of iron, glucose, triglycerides, cholesterol, vitamin C, alkaline phosphatase, and protein and its fractions such as albumin, alpha-, beta-, and gamma-globulins. The data of whites versus blacks, males versus females, and those under versus over 60 years were compared. A significant racial difference was observed for all selected blood components except alpha-1-globulin, cholesterol, and alkaline phosphatase. Albumin, alpha-2-globulin, hemoglobin, hematocrit, serum iron, triglycerides, and vitamin C were significantly higher in whites than in blacks and total protein, beta-1- and gamma-globulins and glucose were significantly higher in blacks than in whites. Males had higher levels of alpha-1- and gamma-globulins, hemoglobin, and hematocrit, and females had higher levels of cholesterol and alkaline phosphatase. Those 60 years and over had higher gamma-globulin and alkaline phosphatase, while adults under 60 years had higher hematocrit. Although results of this study showed significant differences between the races for certain blood parameters and suggest that these differences should be considered in determining guidelines for nutritional evaluation and criteria of diagnosing diseases, further studies are needed to determine the contributions of environment, economic status, and nutritional status to these differences.
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PMID:Comparison of selected blood components by race, sex, and age. 740 85

Ascorbic acid is necessary for expression of the osteoblast phenotype. We examined whether Na(+)-dependent transport is required for MC3T3-E1 preosteoblast cells to respond to vitamin C and investigated the role of membrane transport in the intracellular accumulation and function of ascorbate. MC3T3-E1 cells were found to possess a saturable, stereoselective, Na(+)-dependent ascorbic acid transport activity that is sensitive to the transport inhibitors sulfinpyrazone, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, and phloretin. Transport activity showed no competition with glucose or 2-deoxyglucose and was not inhibited by cytochalasin B, indicating that it is distinct from known hexose transporters. On addition of 100 microM ascorbic acid to the extracellular medium, intracellular concentrations of 10 mM were reached within 5-10 h and remained constant for up to 24 h. A good correlation was observed between intracellular ascorbic acid concentration and rate of hydroxyproline synthesis. Although ascorbic acid was transported preferentially compared with D-isoascorbic acid, both isomers had equivalent activity in stimulating hydroxyproline formation once they entered cells. Marked stereoselectivity for extracellular L-ascorbic acid relative to D-isoascorbic acid was also seen when alkaline phosphatase and total hydroxyproline were measured after 6 days in culture. Moreover, ascorbic acid transport inhibitors that prevented intracellular accumulation of vitamin blocked the synthesis of hydroxyproline. Thus Na(+)-dependent ascorbic acid transport is required for MC3T3-E1 cells to achieve the millimolar intracellular vitamin C concentrations necessary for maximal prolyl hydroxylase activity and expression of the osteoblast phenotype.
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PMID:Requirement for Na(+)-dependent ascorbic acid transport in osteoblast function. 761 63


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