Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

[14C]Glucose taken up by Epidinium ecaudatum caudatum was found in the pool, in the protozoal polysaccharide and in the bacteria associated with the protozoa. The amount incorporated into the polysaccharide depended on the square of the glucose concentration. Evidence was obtained that glucose was probably taken up initially into the pool unchanged, and then rapidly converted into glucose 6-phosphate and maltose which were subsequently hydrolysed to glucose. [14C]-Maltose was taken up at 20 to 30% of the rate of [14C]glucose, with 14C appearing initially in maltose and glucose 6-phosphate. 14C from 14C-labelled soluble starch appeared in the pool as maltose, glucose 6-phosphate and glucose in that order, but incorporation into protozoal polysaccaride was poor. Hexokinase, phosphoglucomutase, alpha-glucan and maltose phosphorylases, glucose 6-phosphatase and maltase activities were found in the protozoa.
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PMID:The uptake and metabolism of glucose, maltose and starch by the rumen ciliate Epidinium ecaudatum caudatum. 18 7

(1,3)-beta-D-Glucan synthase of Candida albicans was rendered soluble by treatment of membrane preparations with the polyoxyethylene ether detergent W-1. Extraction with 0.025% W-1 at 4 degrees C for 24 h effectively solubilized and activated the enzyme. Under these conditions, greater than 85% of the protein in membrane preparations was released, and about 64% of the glucan synthase activity could be recovered in the soluble form. Soluble enzyme activity was stable for more than 12 days at 4 degrees C. Also, glucan synthase activity in the extracted membrane preparations could be activated to achieve more than twice the enzyme activity in the original, unextracted membrane preparations. The soluble glucan synthase had characteristics similar to those of the membrane-bound enzyme. Soluble glucan synthase had an apparent Km of 2.0 mM, and particulate glucan synthase had an apparent Km of 2.5 mM. Kinetics of cilofungin inhibition for both enzyme preparations were noncompetitive, with an apparent Ki of 2.5 microM; both preparations could be inhibited by cilofungin but not by its peptide nucleus or side chain, either alone or in combination. The reaction products from both forms of the enzyme were sensitive to (1,3)-beta-D-glucanase degradation but not to alpha-amylase, alpha-glucosidase, or proteinase K degradation and thus were shown to be beta(1----3) glucan.
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PMID:W-1 solubilization and kinetics of inhibition by cilofungin of Candida albicans (1,3)-beta-D-glucan synthase. 182 95

Gastric intubation was adopted as a means of comparing the effect of two feeding levels, continuous nutrient supply (C) and restricted nutrient supply (R), on the digestive development of pigs weaned at 14 d of age, during the first 5 d post-weaning. The absolute weights of the stomach and the pancreas were significantly greater (P less than 0.001) in C compared with R pigs. The effect was not significant for pancreas weight when expressed per kg body-weight but was significant (P less than 0.05) for stomach weight. The weights of the small intestine (SI), SI mucosa and total mucosal protein were significantly higher (P less than 0.001) in C pigs but protein content per g mucosa was similar in the C and R groups. There was no significant effect of treatment on the activity of lactase (beta-glucosidase; EC 3.2.1.23) or sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) irrespective of the basis of comparison used. The specific activity (mumol/min per g protein) of maltase (alpha-glucosidase; EC 3.2.1.20) and of glucoamylase (glucan-1,4-alpha-glucosidase; EC 3.2.1.3) were similar in C and R groups but activities of maltase (mumol/g mucosa) (P less than 0.05), and maltase and glucoamylase (mol/d) (P less than 0.01) were significantly higher in C pigs. Villous height and crypt depth were significantly greater in C pigs (P less than 0.001 and P less than 0.05 respectively). Enteroglucagon was significantly (P less than 0.05) higher in C compared with R pigs. Xylose absorption and the digestibility of energy were not affected by treatment. Digestibility of dry matter, organic matter, crude protein (nitrogen x 6.25) and carbohydrate were significantly higher (P less than 0.001, P less than 0.01, P less than 0.05 and P less than 0.001 respectively) in R pigs compared with C pigs but the differences were small, ranging from 1.3 to 2.5%. These results demonstrate that (1) nutrient intake in the weaned pig affects the anatomy, morphology and function of the gut, (2) there is considerable 'spare capacity' for digestion of cereal-based diets even in pigs weaned at 14 d of age, (3) measurements in vitro of digestive function are of limited value unless supported by information in vivo on absorption/digestibility.
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PMID:Digestive development of the early-weaned pig. 2. Effect of level of food intake on digestive enzyme activity during the immediate post-weaning period. 204 2

The ligand specificity of the human monocyte receptor that mediates phagocytosis of particulate activators of the human alternative complement pathway was defined by inhibiting the phagocytic response with glycans known to be present in zymosan. When monocytes in monolayers were preincubated with 100 micrograms/ml of beta-glucan and then incubated with 1.25 to 2.5 X 10(6) zymosan particles, the percentage of cells that exhibited phagocytosis was inhibited in a time-dependent manner; maximal inhibition occurred within 20 min of preincubation. beta-Glucan inhibited monocyte phagocytosis of zymosan and rabbit erythrocytes (Er) in a similar dose-dependent fashion and at 100 micrograms/ml reduced monocyte ingestion of 5 X 10(6)/ml zymosan and 2 X 10(8)/ml Er by 63 +/- 8% and 68 +/- 16% (mean +/- SD, n = 3), respectively. The other glycan constituent of zymosan, mannan, was less than 1% as active, and 10 mg/ml of mannan reduced the number of monocytes ingesting zymosan and Er by 56 +/- 12% and 26 +/- 11%, respectively. At concentrations as high as 500 micrograms/ml, beta-glucan had no effect on monocyte Fc, C3b, or fibronectin receptor-mediated functions. Enzymatic hydrolysis of beta-glucan and alpha-mannan with beta-glucosidase or beta-glucanase before their incubation with monocytes abrogated their inhibitory capacity, whereas hydrolysis with alpha-mannosidase or alpha-glucosidase did not. Neither of the two alpha-glucans tested (dextran T-70 and nigeran) affected monocyte ingestion of zymosan particles or sheep erythrocytes (Es) sensitized with rabbit 7S anti-Es (EsIgG) at concentrations as high as 2 mg/ml. In contrast, a number of beta-glucans were active against zymosan but not EsIgG ingestion with a 75% reduction in the number of monocytes ingesting zymosan occurring with 100 micrograms/ml laminarin, 500 micrograms/ml soluble pachyman, and 900 micrograms/ml of soluble pustulan. The galactan, agarose, either in suspensions at 2 mg/ml or in a soluble portion at 600 micrograms/ml failed to affect monocyte ingestion of zymosan particles or Er. Thus, the monocyte receptor for particulate activators that is specifically inhibited by beta-glucan at a rate compatible with a phagocytic process and that recognizes beta-glucans but not alpha-glucans, mannan, or galactan is a beta-glucan receptor.
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PMID:A beta-glucan inhibitable receptor on human monocytes: its identity with the phagocytic receptor for particulate activators of the alternative complement pathway. 257 46

The rumen fungi Neocallimastix patriciarum, Piromonas communis, and a morphologically distinct but unidentified isolate were cultivated on the polysaccharides starch, cellulose, xylan, and their principal component monosaccharides and disaccharides, and the range and specific activities of the glycoside hydrolases formed were monitored using gluco-oligosaccharide and p-nitrophenyl glycoside substrates. A wide range of enzyme activities was detected in preparations from vegetative growth and zoospores of all three isolates. Enzyme activity was also present in the culture medium. The specific activities were affected by the carbohydrate source available in the growth medium, although the more active hydrolases involved in the degradation of plant structural and storage polysaccharides were formed on all seven carbohydrate sources evaluated. Enzyme activities were increased in the zoospore, vegetative, and extracellular preparations after growth on the appropriate structurally related disaccharide or polysaccharide. The hemicellulolytic glycosidases (alpha-L-arabinofuranosidase, beta-D-xylosidase) were most active after growth on xylan, whereas alpha-/beta-glucosidase activity was increased with the corresponding glucan as growth substrate. However, whereas wide-ranging beta-glucosidase activity was detected following growth on maltose or starch, the alpha-glucosidase activities of P. communis were lower or undetectable in vegetative preparations grown on glucose or the beta-glucans cellobiose and cellulose.
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PMID:Glycoside hydrolase enzymes present in the zoospore and vegetative growth stages of the rumen fungi Neocallimastix patriciarum, Piromonas communis, and an unidentified isolate, grown on a range of carbohydrates. 360 11

The synthesis of the glycoprotein enzymes, invertase and acid phosphatase, by protoplasts of Saccharomyces mutant 1016, is inhibited by 2-deoxy-d-glucose (2-dG) after a 20- to 30-min lag period under conditions (external sugar to 2-dG ratio of 40:1) which cause only a slight decrease in total protein synthesis. Formation of one intracellular enzyme, alpha-glucosidase, is also sensitive, but production of another, alkaline phosphatase, is unaffected. A nonmetabolized glucose analogue, 6-deoxy-d-glucose, had no inhibitory effect. The total uptake of external fructose and maltose was decreased by 2-dG after a lag period of about the same duration as that before the inhibition of synthesis of enzymes or of mannan and glucan; during this time 2-dG was taken up by the protoplasts and accumulated primarily as 2-dG-6-phosphate (2-dG-6-P). Studies in vitro showed that 2-dG-6-P inhibits both yeast phosphoglucose isomerase and phosphomannose isomerase. The intracellular levels of the 6-phosphates of glucose, fructose, and mannose did not increase in the presence of 2-dG. We suggest that the high internal level of 2-dG-6-P blocks synthesis of the cell wall polysaccharides and glycoproteins in two ways. It directly inhibits the conversion of fructose-6-P to glucose-6-P and to mannose-6-P. At the same time, it restricts the transport of fructose and maltose into the cell; however, the continuing limited uptake of the sugars still provides sufficient energy for protein synthesis. The cessation of alpha-glucosidase synthesis is probably a result of depletion of the internal pool of maltose (the inducer). Our findings support the suggestion that restriction of synthesis of the carbohydrate moiety of glycoproteins reduces formation of the active enzyme.
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PMID:Inhibition by 2-deoxy-D-glucose of synthesis of glycoprotein enzymes by protoplasts of Saccharomyces: relation to inhibition of sugar uptake and metabolism. 505 66

A number of homokaryons of Schizophyllum commune, which carry various mutations affecting the incompatibility system, and a wild-type homokaryon were grown and examined for differences in the net synthesis of the cell-wall polysaccharides S-glucan, R-glucan, and chitin and in the activity of an enzyme hydrolyzing R-glucan (R-glucanase) in mycelial extracts and culture media. Only slight differences were observed for the accumulation of S-glucan and chitin. In comparison with the wild-type homokaryon, a very high S-glucan/R-glucan ratio was found in a primary B-factor mutant strain. Essentially, wild-type S-glucan/R-glucan ratios were restored in two strains in which additional mutations restored normal morphology: a strain carrying a secondary B-factor mutation and a strain carrying a modifier mutation in addition to the primary B-factor mutation. The S-glucan/R-glucan ratios in three A-factor mutants were intermediate between those of the wild-type homokaryon and the primary B-factor mutant. In young, growing cultures of the various homokaryons, except for the A-factor mutants, a correlation was found between the S-glucan/R-glucan ratios in the cell wall and the activities of R-glucanase in mycelial extracts. A certain specificity of the effect of the studied mutations on enzyme activities was indicated by the fact that, in young cultures, changes in R-glucanase activities were not paralleled by similar changes in the activities of laminarinase and maltase. The results can be correlated with particular morphological features of the homokaryons and, together with earlier results obtained with heterokaryons, indicate the activity of R-glucanase as an integral component of sexual morphogenesis regulated by the incompatibility factors.
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PMID:Biochemistry of sexual morphogenesis in Schizophyllum commune: effect of mutations affecting the incomptability system on cell-wall metabolism. 578 19

The amylolytic activity and especially the production of alpha-amylase (EC 3.2.1.1) and alpha-glucosidase (EC 3.2.1.20) was screened in imperfect fungi, mucoral fungi and some ascomycetes. The character of the polysaccharide system, which is responsible for the utilization of alpha (1 to 4) glucan, was specified with a concomitant screening of growth on soluble starch. The amylolytic activity was found in 29 strains out of the 49 tested.
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PMID:Production of alpha-amylase by microscopic fungi. 616 99

In the pigeon, 70-80% of the activities of maltase (alpha-D-glucoside glucohydrolase EC 3.2.1.20), sucrase (alpha-glucohydrolase, EC 3.2.1.48), isomaltase (dextran 6-alpha-D-glucan hydrolase, EC 3.2.1.10) and glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) were found to be localized in the brush-border membrane of intestinal epithelial cells. Of the total glycosidase activities in the mucosal homogenate, nearly 60 to 70% were recovered in the microsomal (105 000 X g) fraction, about 30% in the mitochondrial (22 000 X g) fraction and less than 5% from the cytosol (105 000 X g supernatant) fraction. The hydrolases were solubilized by digestion with papain but not with trypsin, and the phosphate ion had a protective effect in the solubilization. Amongst detergents, Triton X-100 but not sodium deoxycholate, was found to truly solubilize these enzymes.
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PMID:Studies on the intestinal disaccharidases of the pigeon. II. Subcellular localization and solubilization. 618 28

The toxicity to the cells and protoplasts of Saccharomyces cerevisiae of the sugar analogues modified at carbon 2 increases in the order 2-deoxy-D-glucose (DG), 2-deoxy-2-fluoro-D-glucose (FG) and 2-deoxy-2-fluoro-D-mannose (FM). The fluorohexoses, similarly as DG, behave generally as analogues of both glucose and mannose, depending on the hexose used as a carbon source in the medium. Relative inhibitions of glucan and mannan synthesis in protoplasts were found to be dependent more on glucose and mannose used as the growth support than on the type of the sugar analogue. Certain degree of structural relationship of fluorohexoses to the corresponding natural hexoses was reflected in their effects on growth of intact cells. Growth on glucose was inhibited most effectively by FM, growth on mannose by FG. The data obtained support the view that the sugar analogues interfere mainly with the glucose-mannose interconversion catalyzed by hexosephosphateisomerases. A comparison of the effects of fluorohexoses and DG on the synthesis of extracellular invertase an intracellular alpha-glucosidase and alkaline phosphatase in protoplasts pointed to the fact that all three sugar analogues tested also participate in metabolic control of enzyme synthesis.
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PMID:A comparison of the toxic effects of 2-deoxy-D-glucose and 2-deoxy-2-fluoro-D-hexoses on Saccharomyces cerevisiae cells and protoplasts. 703 85


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