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 activities of brush border membrane-associated hydrolases such as alkaline phosphatase (Alkpase), aminopeptidase, dipeptidyl aminopeptidase IV (DAP-IV), sucrase, lactase, and trehalase were studied in 14 different human colorectal cancer cell lines. The effect of sodium butyrate, a known differentiating agent, and cell growth on the activities of these enzymes was also examined. All 14 cell lines exhibited brush border membrane enzyme activities, and in general, the activity of Alkpase, aminopeptidase, and DAP-IV was much higher than the disaccharidases. However, the specific enzyme activities varied among different cell lines. The induction of Alkpase activity by sodium butyrate occurred in most of the 14 cell lines (2- to 123-fold), while induction of the other enzyme activities was observed in several (1.5- to 3.5-fold). In some instances, butyrate caused a decrease in enzyme activity. There was no statistically significant correlation between the induction of Alkpase activity and that of other enzyme activities by sodium butyrate. Levels of aminopeptidase and DAP-IV activity were found to be dependent on cell density and increased 3- to 4-fold by the tenth day in most of the cell lines. Sodium butyrate altered the subcellular distribution pattern of the disaccharidases, causing a significant increase in activity associated with the soluble (cytoplasmic) fraction. Other enzymes such as Alkpase and DAP-IV continued to be predominantly associated with the membrane fraction in butyrate-treated cells. These data suggest that brush border membrane hydrolase activity and the effect of sodium butyrate may provide useful information regarding the differentiation of human colorectal cancer cells.
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PMID:Effect of growth and sodium butyrate on brush border membrane-associated hydrolases in human colorectal cancer cell lines. 400 36

The influence of two new 1-desoxynojirimycin derivatives, BAY m 1099 and BAY o 1248, on rat small intestinal disaccharidases (sucrase, maltase, isomaltase, glucoamylase, lactase, trehalase) and alkaline phosphatase activity has been investigated in vitro. Both compounds are very potent alpha-glucosidase inhibitors. Tested in the range of 0.1-5.0 micrograms/ml, inhibition is strongest on sucrase (up to 97.1%) and glucoamylase (up to 96.7%). BAY m 1099 also reduced (up to 56.4%) beta-galactosidase (lactase) activity. For both inhibitors a competitive type of sucrase inhibition was demonstrated (Lineweaver-Burk plot). Affinity versus sucrase was unusually tight. The Ki of BAY m 1099 versus sucrase amounted to 1.14 x 10(-7) M and of BAY o 1248 to 6.92 X 10(-8) M (Dixon plot). Both inhibitors did not impair active transport of L-leucine or methyl-alpha-D-glucoside into everted rings of rat jejunum in vitro.
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PMID:Effect of 1-desoxynojirimycin derivatives on small intestinal disaccharidase activities and on active transport in vitro. 403 92

The influence of hydrocortisone on the differentiation and proliferation of human fetal small intestine was studied. Fetal intestine (12- to 14-week gestation) was cultured during 5 days at 37 degrees C in serum-free Leibovitz L-15 medium alone or supplemented with hydrocortisone (12.5, 25, and 50 ng/ml). The addition of different concentrations of hormone did not affect the morphology of the intestinal explants. Brush border membrane hydrolytic activities, namely, sucrase, lactase, glucoamylase, trehalase, and alkaline phosphatase activities, were assayed in the intestinal tissue. A specific increase of lactase and alkaline phosphatase activities was induced by the addition of 25 and 50 ng hydrocortisone/ml culture medium. The DNA synthesis evaluated by the incorporation of [3H]thymidine was increased by the addition of 50 ng hydrocortisone/ml. The sites of incorporation into the different layers of the intestinal wall were studied by radioautography. The incorporation of the radioactive precursor occurred mainly in the epithelium and to a lesser degree in the mesenchyme and muscular layers. Labeled epithelial nuclei were located in the intervillous areas and developing crypts but not on the villi. The addition of hydrocortisone induced a significant increase of the labeling index of the epithelial cells. The present work provided for the first time some basic data on the influence of hydrocortisone on brush border hydrolytic activities and on epithelial cell proliferation of human fetal small intestine.
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PMID:Influence of hydrocortisone on human fetal small intestine in organ culture. 406 77

Mucoid enteropathy was induced experimentally by ligation of the cecum, and the activities of mucosal disaccharidases and alkaline phosphatase were measured at different locations along the small intestine of the sick and control rabbits. In the duodenum of rabbits with mucoid enteropathy, the activity of acid beta-galactosidase II was elevated and hetero beta-galactosidase declined. In the jejunum, the activities of lactase, acid beta-galactosidase I and II, hetero beta-galactosidase, trehalase, sucrase and alkaline phosphatase were significantly lower in animals with mucoid enteropathy. In the ileum, acid beta-galactosidase II, hetero beta-galactosidase, maltase, trehalase, sucrase and alkaline phosphatase showed decreased activity in rabbits with mucoid enteropathy.
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PMID:Intestinal disaccharidase and alkaline phosphatase activities in experimental rabbit mucoid enteropathy. 409

1. A method for the preparation of brush border from rabbit kidneys is described. Contamination by other organelles was checked by electron microscopy and by the assay of marker enzymes and was low. 2. Seven enzymes, all hydrolases, were substantially enriched in the brush-border preparation and are considered to be primarily located in this structure. They are: alkaline phosphatase, maltase, trehalase, aminopeptidase A, aminopeptidase M, gamma-glutamyl transpeptidase and a neutral peptidase assayed by its ability to hydrolyse [(125)I]iodoinsulin B chain. 3. Adenosine triphosphatases were also present in the preparation, but showed lower enrichments. 4. Alkaline phosphatase was the most active phosphatase present in the preparation. The weak hydrolysis of AMP may well have been due to this enzyme rather than a specific 5'-nucleotidase. 5. The two disaccharidases in brush border were distinguished by the relative heat-stability of trehalase compared with that of maltase. 6. The individuality of the four peptidases was established by several means. The neutral peptidase and aminopeptidase M, both of which can attack insulin B chain, differed not only in response to inhibitors and activators but also in the inhibitory effect of a guinea-pig antiserum raised to rabbit aminopeptidase M. This antiserum inhibited both the purified and the brush-border activities of aminopeptidase M. The neutral peptidase and gamma-glutamyl transpeptidase were unaffected but aminopeptidase A was weakly inhibited. The characteristic responses to Ca(2+) and serine with borate served to distinguish aminopeptidase A and gamma-glutamyl transpeptidase from other peptidases. 7. No dipeptidases, tripeptidases or carboxypeptidases were identified as brush-border enzymes. 8. Incubation of brush border with papain released almost all the aminopeptidase M activity but only about half the activities of maltase, gamma-glutamyl transpeptidase and aminopeptidase A. No release of alkaline phosphatase, trehalase or the neutral peptidase was observed.
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PMID:Studies on the enzymology of purified preparations of brush border from rabbit kidney. 414 72

Several hydrolase activities characteristic of the apical brush border membrane of renal proximal tubule, leucine aminopeptidase, gamma-glutamyl transpeptidase, alkaline phosphatase, maltase, and trehalase, were identified in cultures of the LLC-PK1 kidney epithelial cell line. A coordinate increase in activities of these enzymes was observed upon development of a confluent cell density and functional membrane polarization. Further large progressive increases in individual hydrolase activities were induced after the addition of compounds known as differentiation inducers. Hexamethylene bisacetamide preferentially induced increased trehalase and maltase activities. Induced trehalase activity exhibited an increased Vmax but a similar Km compared with activity in control extracts. Induction required protein synthesis and was dependent on inducer concentration and exposure time. Treatment of confluent cultures with N,N'-dimethylformamide triggered an induction of maltase, trehalase, alkaline phosphatase, and gamma-glutamyl transpeptidase activities, whereas dimethylsulfoxide induced trehalase and gamma-glutamyl transpeptidase activities. Increased leucine aminopeptidase and maltase activities were observed after addition of the phosphodiesterase inhibitor 1-methyl-3-isobutylxanthine. Induction of trehalase activity by N,N'-dimethylformamide was reversible over a 4-day period after removal of inducer, but effects of hexamethylene bisacetamide were irreversible. These results suggest that the LLC-PK1 cell line reproducibly develops differentiation-specific characteristics under defined conditions in cell culture, which can be individually modulated by chemicals known as inducers of cell differentiation.
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PMID:Induction of microvillar hydrolase activities by cell density and exogenous differentiation inducers in an established kidney epithelial cell line (LLC-PK1). 609 Apr 80

The influence of hydrocortisone (10(-8)--10(-5) M) and thyroxine (10 (-9)--10(-6) M) on intestinal epithelial cell differentiation and proliferation have been studied using explants of suckling mouse jejunum maintained in serum-free organ culture. Hydrocortisone induced the appearance of sucrase activity and increased trehalase, glucoamylase, lactase and alkaline phosphatase activities. Thyroxine was completely ineffective at all the concentrations used. None of these hormones affected the mitotic activity or the 3H-thymidine incorporation into DNA. These results demonstrate that hydrocortisone but not thyroxine acts directly on intestinal brush border membrane differentiation and that both hormones do not influence the proliferation of the epithelial cells during postnatal development.
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PMID:Comparative study of the effect of hydrocortisone and thyroxine on suckling mouse small intestine in organ culture. 614 44

In Saccharomyces cerevisiae, trehalase activity in crude extracts obtained from wild type cells was activated about 3-fold by preincubation with cAMP and ATP. The inactive trehalase fractionated by DEAE-Sephacel chromatography was activated by the addition of the cAMP-dependent protein kinase fraction from wild type cells in the presence of cAMP and ATP. Using the crude extract obtained from bcy1 mutant cells which were deficient in the regulatory subunit of cAMP-dependent protein kinase, the stimulation of trehalase activity was observed in the absence of cAMP. The cAMP-dependent protein kinase of CYR3 mutant cells which had a high Ka value for cAMP in the phosphorylation reaction required a high cAMP concentration for activation of trehalase. Increased activation of partially purified inactive trehalase (Mr = 320,000) was observed to correlate with increased phosphorylation of a protein (Mr = 80,000) identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The assay results using various mutants altered in cAMP metabolism indicated that the activation and phosphorylation of inactive trehalase fractions depended on the cAMP concentration accumulated in mutant cells. Inactivation and dephosphorylation of active trehalase fractions were observed by treatment with alkaline phosphatase or crude cell extracts. The results indicated that the conversion of inactive form of trehalase to the active form is regulated by cAMP through cAMP-dependent protein kinase.
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PMID:Genetic and biochemical evidence that trehalase is a substrate of cAMP-dependent protein kinase in yeast. 630 18

Apical membrane vesicles were prepared from confluent monolayers of LLC-PK1 cells grown upon microcarrier beads. The final membrane preparation, obtained by a modified divalent cation precipitation technique, was enriched in alkaline phosphatase, leucine aminopeptidase and trehalase (8-fold compared to the initial homogenate). Analysis of phosphate uptake into the vesicles identified a specific sodium-dependent pathway. Lithium and other cations were unable to replace sodium. At 100 mmol/l sodium and pH 7.4, an apparent Km for phosphate of 99 +/- 19 mumol/l and an apparent Ki for arsenate of 1.9 mmol/l were found. Analysis of the sodium activation of phosphate uptake gave an apparent Km for sodium of 32 +/- 12 mmol/l and suggested the involvement of two sodium ions in the transport mechanism. Sodium modified the apparent Km of the transport system for phosphate. The rate of sodium-dependent phosphate uptake was higher at pH 6.4 than at pH 7.4. At both pH values, an inside negative membrane potential (potassium gradient plus valinomycin) had no stimulatory effect on the rate of the sodium-dependent component of phosphate uptake. It is concluded that the apical membrane of LLC-PK1 cells contains a sodium-phosphate cotransport system with a stoichiometry of 2 sodium ions: 1 phosphate anion.
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PMID:Sodium-dependent phosphate transport by apical membrane vesicles from a cultured renal epithelial cell line (LLC-PK1). 669 95

Intestinal metaplasia is defined as the appearance of intestinal epithelium in the stomach. Intestinal metaplasia is frequently found in populations with a high incidence of gastric cancer. Macroscopic demonstration of sucrase and trehalase with Tes-tape in many resected stomachs yielded new information for understanding the nature of intestinal metaplasia. Intestinal metaplasia can be classified into two types, complete and incomplete. The former is associated with the presence of sucrase, trehalase, leucine aminopeptidase, alkaline phosphatase, goblet cells and Paneth cells, and the latter with that of sucrase, leucine aminopeptidase and goblet cells, but not trehalase or Paneth cells. Goblet cells in the complete type of intestinal metaplasia contain sialomucin, as does the small intestine, while those in the incomplete type contain sulphomucin and sialomucin, as does the large intestine. Well-differentiated adenocarcinoma is closely related to intestinal metaplasia, especially the incomplete type. Atypical epithelium of intestinal metaplasia has been proposed as a more proximate stage of gastric cancer. Intestinal metaplasia can be diagnosed by staining with dye under endoscopic observation. A reduced level of pepsinogen I in the blood reflects the presence of severe intestinal metaplasia, which is understood to be a sign of high risk of gastric cancer. Intestinal metaplasia is supposed to be produced by components of food. Mutagens/carcinogens such as N-methyl-N'-nitro-soguanidine and N-propyl-N'-nitro-N-nitrosoguanidine can produce intestinal metaplasia in the glandular stomach of rats and gastric cancers. The formation of intestinal metaplasia precedes the appearance of adenocarcinoma in the glandular stomach. Intestinal metaplasia, which is a kind of host reaction to environmental agents, may result either from genetic change - change in DNA structure - or from epigenetic change - change in the differentiation mechanism. Preventive measures could be developed to suppress the development of intestinal metaplasia and to suppress the process of conversion of metaplastic cells to cancer cells.
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PMID:Intestinal metaplasia of the stomach as a precancerous stage. 675 88


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