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

---

Query: EC:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A close relationship exists between relative disaccharidase activities (maltase, sucrase, trehalase, palatinase, turanase, lactase, and cellobiase) in amniotic fluid and corresponding jejunal mucosa of five human fetuses (16 to 21 weeks of gestation) suggesting that these intestinal enzymes pass into amniotic fluid. Serial determination of disaccharidase activities in amniotic fluid samples collected between 10 and 42 weeks of gestation showed maximum mean activities at 14 to 17 weeks of gestation and a rapid drop to less than 12 per cent maximum values at about 22 weeks. This drop is probably caused by combined effects of decreased extrusion rate of intestinal disaccharidases and increased reabsorption of the enzymes in swallowed amniotic fluid with fetal development.
...
PMID:Developmental patterns of intestinal disaccharidases in human amniotic fluid. 64 87

Activities of several hydrolases were studied in blood serum, synovial fluid and musculus femoris of rats with adjuvant arthritis. Alterations in activity of some hydrolases in blood serum were investigated after treatment of animals with nonsteroid antiinflammatory drugs (indometacin, aspirin, bruphene), prednisolone or after the treatment with immunodepressants (imurane, D-penicillamine) and theophylline. Distinct activation of several lysosomal enzymes was observed in rats with arthritis: acidic cathepsins and beta-D-glucuronidase--in all the samples studied; beta-D-galactosidase--in synovial fluid and musculus femoris; hyaluronidase--in synovial fluid and blood serum as well as alpha-D-galactosidase and arylsulfatases (A + B)--in the latter. Activation of these enzymes was accompanied by a decrease in activity of other hydrolases: beta-D-glucosidase, hyaluronidase and alpha-D-galactosidase--in musculus femoris; alpha-D- and beta-D-glucosidases--in blood serum. In treatment of the impaired rats aspirin was the most effective drug, bruphene was less effective. Only theophylline among the drugs studied activated distinctly alpha-D-glucosidase in blood serum. Combination of nonsteroid antiinflammatory drugs (like aspirin and bruphene) with theophylline was apparently the most suitable way for treatment of arthritis under the experimental conditions.
...
PMID:[Hydrolytic enzymes in biological fluids and skeletal muscle of rats with adjuvant arthritis]. 66 68

The pH optima and apparent Km and Vmax values were determined for nine glycosidases of the retinal pigment epithelium (RPE) of the calf. In terms of micromoles of substrate cleaved per milligram protein per hour, the following relative order of enzymatic activities was observed: beta-N-acetylglucosaminidase greater than alpha-glucosidase = beta-N-acetylgalactosaminidase greater than alpha-mannosidase greater than beta-galactosidase greater than beta-glucosidase greater than alpha-fucosidase greater than alpha-galactosidase greater than beta-glucuronidase. The pH optimum of each of these enzymes was in the acidic range (below pH 6). All these findings refer to enzymatic activities of bovine RPE preparations obtained by the brushing procedure of Glocklin and Potts and washing as described by Berman and Feeney. Thus they may relate to those activities associated with particulate components of the RPE cell and not to the more soluble glycosidases. The distribution of the glycosidases between the washes of the cells and the final pellet of bovine RPE cells was examined. The activities of 10 glycosidases in the RPE of the embryonic chick were also examined. Neither beta-mannosidase nor beta-fucosidase activities could be detected in washed bovine RPE cells, although beta-mannosidase was detected in RPE of the embryonic chick. The presence of isoenzymes of beta-glucuronidase in bovine RPE was indicated. Specificity by beta-glucuronidase of bovine RPE for synthetic substrates was observed.
...
PMID:Glycosidases of the retinal pigment epithelium. 70 Sep 67

Tissues of rats with adjuvant arthritis manifested differences in activity and distribution between free, latent and membrane-bound forms of acid catepsins, alpha-D- and beta-D-galactosidases, alpha-D- and beta-D-glucosidases, beta-D-glucorunidase, hyaluronidase, acid phosphatase, arylsulphatases (A+B). Activation of certain hydrolytic enzymes is observed in tissues of the liver, kidneys, heart and spleen: a rise in total activity (of arylsulphatase in the liver and acid catepsins in the spleen; hyaluronidase in the kidneys, beta-D-glucuronidase in the heart) and a change in the ratio of different forms with a simultaneous increase in the activity of free form (of hyaluronidase in the spleen, acid phosphatase in the heart and liver). Inhibition of alpha-D-glucosidase in the liver and beta-D-glucosidase in the spleen is also detected. A decrease in the activity of beta-D-glucuronidase in the spleen is pronounced in a significant decrease in the activity of each enzyme free form with no changes in the total activity.
...
PMID:[Hydrolytic enzymes of rat tissues with adjuvant arthritis]. 72 90

Calf pancreas microsomes incorporated radioactively labeled D-glucose from UDP-D-glucose into products extracted with chloroform/methanol (2:1, v/v), chloroform/methanol/water (10:102.5, v/v), and into the residual precipitate, with a pH optimum in Tris/maleate buffer of about 5.3. The chloroform/methanol extract contained a single 14C-labeled acidic product, which was identified as dolichyl beta-D-glucosyl phosphate. It was stable to mild alkali, yielded D-[14C]glucose upon mild acid hydrolysis, and a 14C-labeled compound with the chromatographic mobility of 1,6-anhydro-beta-D-glucopyranosyl upon hot alkali treatment. The [14C]glucolipid had the same chromatographic mobility as dolichyl beta-D-[14C]mannosyl phosphate, and its formation was stimulated by exogenous dolichyl phosphate. The chloroform/methanol/water extract contained radioactive lipid-bound oligosaccharides which were retained on DEAE-cellulose more strongly than dolichyl D-[14C]glucosyl phosphate. They were stable to mild alkali, but labile to acid and hot alkali. Acid treatment yielded a D-glucose-labeled oligosaccharide fraction which was shown by gel filtration to be slightly larger than most of the D-mannose-labeled oligosaccharides. About 80% of the radioactive D-glucose residues could be removed with alpha-glucosidase, but not with beta-glucosidase. Pancreatic dolichyl beta-D-[14C]glucosyl phosphate incubated with calf pancreas microsomes served as direct donor of D-glucosyl residues to lipid-bound oligosaccharides and to the precipitate. These oligosaccharides had the same size as those labeled from UDP-D-[14C]glucose, and the D-[14C]glucose residues could also be removed with alpha-glucosidase.
...
PMID:Glucosyltransferase activity in calf pancreas microsomes. Formation of dolichyl D[14C]glucosyl phosphate and 14C-labeled lipid-linked oligosaccharides from UDP-D-[14C]glucose. 84 29

A unique demonstration is presented of the capacity of glycosidases to create anomeric configuration de novo. Purifed Candida tropicalis alpha-glucosidase and sweet almond beta-glucosidase have been found to attack the same substrate, D-glucal, and to convert this unusual glycosyl substrate (which lacks alpha or beta anomeric configuration) to 2-deoxy-alpha-(or beta-) D-glucose, respectively. The stereospecificity of the hydration reaction catalyzed by each enzyme in D2O was revealed by the use of high-resolution (270 MHz) 1H magnetic resonance spectroscopy. The alpha-glucosidase caused a specific axial protonation (deuteration) of D-glucal at C-2, and formation of 2-deoxy-alpha-D-[2(a)-2H]glucose. The beta-glucosidase catalyzed an oppositely directed axial protonation at C-2 and formation of 2-deoxy-beta-D-[2(e)-2H]glucose. These results are not accounted for by the generally accepted mechanisms of carbohydrase action derived from studies with glycosidically linked substrates alone. D-Glucal apparently binds to the enzymes with essentially the same overall orientation as the D-glucosyl moiety of glycosidically linked substrates (with the double bond of D-glucal lying essentially in the plane of the similarly bound D-glucosyl group). Thus, the alpha-glucosidase evidently protonates D-glucal from above the double bond and alpha-D-glucosidic substrates from below the glycosidic oxygen; beta-glucosidase apparently protonates D-glucal from below the double bond and beta-D-glucosides from above the glycosidic oxygen. A detailed mechanism is proposed for the hydration of D-glucal by each enzyme, involving an incipient glycosyl carbonium ion and assuming the presence at the active site of two carboxyl groups arranged to account for catalysis of glycosylations from glycosidically linked substrates. That D-glucal serves as a glycosyl substrate for these enzymes strongly supports the concept that glycosidases and glycosyltransferases are catalysts of glycosylation (i.e., glycosylases), since this concept does not make the usual assumption that carbohydrases are restricted to acting on substrates having a glycosidic bond and either alph- or beta-anomeric configuration.
...
PMID:Scope and mechanism of carbohydrase action: stereospecific hydration of D-glucal catalyzed by alpha- and beta-glucosidase. 87 25

Intestinal mucosa and pancreas from purebred Beagle dogs were assayed for carbohydrase activity, using several methods of tissue treatment. The enzymes found and studied were alpha-amylase, sucrase, lactase, amyloglucosidase, cellobiase, maltase, and isomaltase. Experiments using polyacrylamide gel columns and heat inactivation showed the presence of an isozyme of maltase which degrades isomaltose. This activity had not been previously demonstrated in dogs. An optimal standard procedure is presented for the preparation and assay of canine digestive enzymes. A statistical analysis of variance of the results showed that the variance was primarily associated with differences among dogs and not by variance within the procedure. When the different extraction procedures were used, results indicated that the level of enzymes detected differed with the method of treatment.
...
PMID:Detection and definition of canine intestinal carbohydrases, using a standardized method. 88 14

Rats with chronic uremia following five-sixths nephrectomy showed a significant fall in the sucrase and maltase activities in the small intestinal mucosa, the lactase and cellobiase activities in contrast remained uninfluenced. The activity of the L-leucyl-L-proline and L-methionyl-L-proline dipeptidases in the small intestinal mucosa was significantly increased, while the activities of seven other dipeptidases studied were unaffected. The mucosal protein and DNA content likewise remained unchanged. Occasional slight alterations of the mucosa were the only finding at histology.
...
PMID:Activities of intestinal enzymes in experimental chronic renal insufficiency. 88 89

The latency of the alpha-glucosidase activity of intact rat liver lysosomes was studied by using four substrates (glycogen, maltose, p-nitrophenyl, alpha-glucoside, alpha-fluoroglucoside) at a range of substrate concentrations. The results indicate that the entire lysosome population is impermeable to glycogen and maltose, but a proportion of lysosomes are permeable to alpha-fluoroglucoside and a still higher proportion permeable to p-nitrophenyl alpha-glucoside. Incubation at 37 degrees C in an osmotically protected buffer of of pH 5.0 caused lysosomes to become permeable to previously impermeant substrates and ultimately to release their alpha-glucosidase into the medium. The latencies of lysosomal beta-glucosidase and beta-galactosidase were examined by using p-nitrophenyl beta-glucoside and beta-galactoside as substrates. The results indicate permeability properties to these substrates similar to that to p-nitrophenyl alpha-glucoside. On incubation in an osmotically protected buffer of pH 5, lysosomes progressively released their beta-galactosidase in soluble form, but beta-glucosidase remained attached to sedimentable material. Lysosomal beta-glucosidase was inhibited by 0.1% Triton X-100; alpha-glucosidase and beta-galactosidase were not inhibited.
...
PMID:Latency of some glycosidases of rat liver lysosomes. 101 43

Lactase and cellobiase were detectable in the fetal intestine by the 3rd month of gestation, and although there was little change by the 9th month, maximal levels were reached at birth and steadily declined after 4 months. Conversely maltase, sucrase and trehalase were barely discernible in the fetus, maltase being present at low levels at birth, but all increased during the suckling period to attain adult levels by 7 months of age. Alkaline phosphatase activity matured earlier than did disaccharidase activity. Mucosal enzymes other than alkaline phosphatase were virtually absent from meconium and the large intestine. Continued ingestion of lactose could be detrimental in foals suffering from severe diarrhoea.
...
PMID:The development and distribution of mucosal enzymes in the small intestine of the fetus and young foal. 106 Aug 71


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---