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:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of Eikenella corrodens adherence to human buccal epithelial cells in vitro was studied. Initial experiments to determine the optimal conditions for adherence of E. corrodens to buccal epithelial cells showed that adherence was dependent on time, temperature, bacterial concentration, and pH. Different strains of E. corrodens varied in their ability to adhere, and strain 1073 showed the greatest ability in adherence. Strain 1073 was selected for studies of adherence mechanisms. Trypsin treatment or heating (100 degrees C, 10 min) of the bacterial cells abolished their capacity to adhere to buccal epithelial cells. Treatment of buccal epithelial cells with trypsin also abolished adherence of E. corrodens 1073, whereas neuraminidase treatment of buccal epithelial cells enhanced the adherence. The adherence was inhibited by ethylenediaminetetraacetic acid and restored by adding Ca2+. The adherence was remarkably inhibited by sugars containing D-galactose and n-acetyl-D-galactosamine. Treatment of neuraminidase-treated epithelial cells with sodium metaperiodate or alpha- and beta-galactosidase did not decrease the adherence. These data suggest that adherence of E. corrodens 1073 to human buccal epithelial cells may require the interaction of lectin-like proteins on the bacterial surface with galactose-like receptors on the surface of epithelial cells.
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PMID:Eikenella corrodens adherence to human buccal epithelial cells. 626 Jun 61

Extra-embryonic endoderm cells from gastrulating chick embryos possess Ca2+-dependent and Ca2+-independent adhesive mechanisms. These cells also contain an endogenous beta-D-galactoside-binding lectin and cell surface receptors bearing galactose groups. The endogenous lectin inhibits cellular adhesion. To test whether the adhesive interactions involving lectin and galactose molecules are part of the Ca2+-independent or Ca2+-dependent adhesive mechanism, dissociated cells which were preincubated in beta-galactosidase were allowed to aggregate in the presence and absence of Ca2+ ions. Significant decreases in adhesion were observed in both cases. Cells were also allowed to aggregate in the presence and absence of Ca2+ ions when blastoderm lectin was present in the medium. Adhesion was decreased in both cases. The results suggest that cell surface galactose groups and the beta-D-galactoside-binding lectin are involved in Ca2+-independent adhesion.
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PMID:Calcium-independent adhesion of extra-embryonic endoderm cells from the early chick blastoderm is inhibited by the blastoderm beta-D-galactoside-binding lectin and by beta-galactosidase. 640 23

Absorption of dietary energy, nitrogen, carbohydrates and calcium, and retention of nitrogen and calcium were studied in 20 children with protein-energy malnutrition of the edematous type, using metabolic balance techniques and breath H2 analysis, to assess the advisability of using lactose-containing formulas in the rehabilitation of severely malnourished children. Ten patients received for 45 days a diet formula based on cows' milk (intact milk) and 10 similar children received the same formula pretreated with beta-galactosidase to hydrolyze the lactose (hydrolyzed milk). Dietary intakes were gradually increased to reach, on the 8th day, 4 g of protein and 150 kcal/kg. There were no differences between groups with respect to absorption or retention of the index nutrients. Postprandial carbohydrate malabsorption was occasionally observed in two patients with servings of the intact milk formula, and in one with the hydrolyzed milk diet. When the nutritional quality of a diet is assessed, the amount of nutrients that are absorbed and utilized are more important than the small, incompletely absorbed fractions that do not have significant metabolic or clinical implications. Therefore, the use of milk as the protein source for recovery diets is not contraindicated in the routine treatment of PEM.
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PMID:The effect of dietary lactose on the early recovery from protein-energy malnutrition. II. Indices of nutrient absorption. 643 95

The effect of diphenylhydantoin (DPH) on the release of lysosomal enzymes during resorption of cultured mouse calvarial bone was studied. The enzyme activities of beta-glucuronidase and beta-galactosidase in the culture medium was taken as indicators for lysosomal enzyme release. In concentrations 50 micrograms/ml or higher, DPH inhibited the release of beta-glucuronidase and beta-galactosidase in parallel with bone resorption as indicated by reduced release of 45Ca, Ca2+, Pi and hydroxyproline. The release of the cytosolic enzyme lactate dehydrogenase was not influenced by concentrations of DPH up to 50 micrograms/ml but higher concentrations caused an increased release indicating cell injury. When bone resorption was stimulated by prostaglandin E2, DPH (50 micrograms/ml) also reduced the mobilization of bone mineral and the release of beta-glucuronidase without influencing the release of lactate dehydrogenase. It is suggested that DPH by interfering with cellular release processes reduces the resorption of bone.
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PMID:Influence of diphenylhydantoin on lysosomal enzyme release during bone resorption in vitro. 677 82

Pig intestinal lactase/phlorizin hydrolase (EC 3.2.1.23/62) was purified in its amphiphilic form by immunoadsorbent chromatography. The purified enzyme was free of other known brush border enzymes and appeared homogeneous in immunoelectrophoresis and polyacrylamide gel electrophoresis in the presence of SDS. Pig lactase/phlorizin hydrolase was shown to have the same quaternary structure as the human enzyme, i.e., built up of two polypeptides of the same molecular weight (160000). In addition to hydrolyzing lactose, phlorizin and a number of synthetic substrates, both the human and the pig enzyme were shown to have a considerable activity against cellotriose and cellotetraose, and a low but significant activity against cellulose. The lactase/phlorizin hydrolase isolated from pigs in which the pancreatic ducts had been disconnected 3 days before death and from Ca2+-precipitated enterocyte membranes (basolateral and intracellular membranes) exhibited in SDS-polyacrylamide gel electrophoresis the same size of constituent polypeptides and the same catalytic and immunological properties as a normal brush border lactase/phlorizin hydrolase.
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PMID:Further characterization of intestinal lactase/phlorizin hydrolase. 681 89

Delta toxin, one of at least four toxins produced by pathogenic strains of the skin bacterium Staphylococcus aureus, is an amphipathic polypeptide possessing hemolytic and cytolytic activity. Delta toxin stimulates high levels of phospholipase A2 activity in 3T3 mouse fibroblasts with concomitant synthesis and release of prostaglandins. Alpha toxin, another hemolytic toxin produced by strains of S. aureus, did not stimulate phospholipase A2 or prostaglandin release in these cells. Analysis of the release of lactate dehydrogenase and beta-galactosidase (cytoplasmic and lysosomal marker enzymes, respectively) from delta-toxin-treated cells indicated that cytolytic concentrations of the toxin damage the cell-surface membrane more extensively than lysosomal membranes. During a 30 min exposure, delta toxin stimulated 3T3 cells to hydrolyze up to 32% of the lipids biosynthetically labeled by incorporation of [3H]arachidonic acid. A relatively high percentage of the free arachidonic acid formed in delta-toxin-treated 3T3 cells was converted to prostaglandins (up to 41.3% and 8.3% converted to chromatographically identifiable prostaglandins E2 and F2 alpha, respectively, in 30 min), with optimal conversion occurring at sublytic toxin concentrations. The degree of activation of phospholipase A2 in 3T3 cells by a range of concentrations of delta toxin correlates with cytotoxicity assessed by failure to exclude trypan blue dye. Analysis of the calcium dependency of the toxin-activated phospholipase A2 was consistent with a cell-surface, Ca2+-dependent enzyme. The phospholipase A2 exhibits a degree of specificity for substrate lipids containing polyunsaturated fatty acid residues which can serve as precursors for prostaglandin formation. Enzymatic activity was not inhibited by diisopropylfluorophosphate (5 mM), N-ethylmaleimide (5 mM) or p-bromophenacylbromide (0.1 mM). Delta toxin did not activate detectable phospholipase A2 in subcellular preparations containing plasma membrane.
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PMID:Staphylococcal delta toxin stimulates endogenous phospholipase A2 activity and prostaglandin synthesis in fibroblasts. 721 81

The effect of indomethacin on bone resorption was studied in an organ culture system, using calvarial bones from 6--7-day-old mice. It was found that indomethacin inhibited spontaneous bone resorption, as estimated by decreased release of 45Ca, Ca2+ and Pi. Indomethacin reduced the release of beta-glucuronidase, beta-galactosidase and beta-N-acetylglucosaminidase, diminished glucose consumption and lactate production, but showed no effect on the release of lactate dehydrogenase. No inhibitory effect of indomethacin on the release of 45Ca stimulated by parathyroid hormone, prostaglandin E2 or 1 alpha(OH)D3 could be registered. 5,8,11,14-eicosatetraynoic acid, an inhibitor of both cyclo- and lipoxygenase pathway of arachidonate metabolism, reduced the spontaneous release of 45Ca, whereas the selective lipoxygenase inhibitor 5,8,11-eicosatriynoic acid was without effect. The results presented indicate that indomethacin may have an inhibitory effect upon the osteoclasts, probably by decreased metabolism of arachidonic acid via the cyclo-oxygenase pathway. A possible relationship between this finding and the pathogenesis of rapid destruction of articular bone in osteoarthritic patients treated with indomethacin is discussed.
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PMID:Indomethacin inhibits bone resorption and lysosomal enzyme release from bone in organ culture. 745 22

We have raised mouse monoclonal antibodies to eight synthetic peptides corresponding to different regions of the human cystic fibrosis transmembrane conductance regulator (CFTR) and rabbit polyclonal antisera to beta-galactosidase fusion proteins which encompass three different regions of CFTR. Immunoblot, immunoprecipitation, immunofluorescence and immunocytochemical experiments demonstrate that, in addition to recognising CFTR, these antibodies recognise one or more immunologically related proteins with a similar molecular mass, calcium responsiveness and tissue distribution to CFTR.
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PMID:Production and characterisation of monoclonal and polyclonal antibodies to different regions of the cystic fibrosis transmembrane conductance regulator (CFTR): detection of immunologically related proteins. 754 88

This study demonstrates that beta-glucuronidase from rat preputial glands binds with high affinity to spermatozoa from the cauda epididymis. The binding was calcium-independent and was inhibited by mannose-6-phosphate, but not by other phosphorylated or non-phosphorylated sugars. Binding was also inhibited by alpha-mannosidase from Dictyostelium discoideum, an enzyme known to have mannose-6-phosphate as the ligand. From solubilized sperm membranes, a protein of > 200 kDa and one of 45 kDa, were absorbed to a column of D. discoideum enzyme and to a phosphomannan column respectively, and eluted with mannose-6-phosphate. According to histochemical observations at the light and the electron microscopic level, gold particles coated with the enzyme became bound to the external surface of the plasmalemma in the acrosomal region of caudal spermatozoa. Similar labelling was observed using gold particles coated with antibodies against the rat 300 kDa phosphomannosyl receptor. The existence of phosphomannosyl receptors on the sperm plasma membrane, and our previous demonstration of the presence of affinity sites for epididymal beta-galactosidase on these gametes which is inhibited by phosphofructosyl derivatives, suggest strongly that maturing spermatozoa could be a target for glycosidases secreted into the lumen of the cauda epididymis, which then become bound to these cells via different ligand-receptor systems.
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PMID:Phosphomannosyl receptors on the surface of spermatozoa from the cauda epididymis of the rat. 755 73

beta-galactosidase (Escherichia coli) with a His substituted for Glu-461 retained about 10% of its normal activity in the absence of divalent metals but was inactivated rather than activated by Mg2+, Mn2+, Zn2+, Ni2+, Cu2+, and Co2+. Since Zn2+, Ni2+, Cu2+, and Co2+ do not interact with wild type beta-galactosidase while Mg2+ and Mn2+ activate and Ca2+ binds but has no effect on wild type beta-galactosidase activity, the substituted enzyme has very different divalent metal interactions. A much larger amount of Mg2+ than of the other divalent metal ions was needed to inactivate the substituted enzyme at pH 7 (half-maximal activity was at 12.5 mM Mg2+ while the half-maximal activities with the other metals were at micromolar levels) compared to the amount of Mg2+ needed to activate the wild type enzyme. The inactivation of E461H-beta-galactosidase caused by Mg2+ took about 20 min. Reactivation by removal of the divalent metal took about 60 min. Interaction with Mg2+ was about 10(7)-fold stronger at pH 9 than at pH 7, and inactivation occurred in less than 2 min at higher pH values. "Galactosylation" (k2, cleavage of the glycosidic bond) seemed to be rate-limiting for E461H-beta-galactosidase at pH values above 6 with both o-nitrophenyl beta-D-galactopyranoside and p-nitrophenyl beta-D-galactopyranoside in both the presence and absence of Mg2+. Mg2+ caused decreases (about 50-fold) of the k2 values of E461H-beta-galactosidase (apparent pKa was about 6.8).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:E461H-beta-galactosidase (Escherichia coli): altered divalent metal specificity and slow but reversible metal inactivation. 757 31


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