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

The paper describes a number of tests for the rapid detection of glycosidases including alpha-glucosidase, beta-glucosidase, beta-glucuronidase, beta-xylosidase and alpha-fucosidase. The methods use heavy suspensions of viable but non-multiplying bacteria in a buffered solution of a chromogenic substrate. The results of the tests are readable within 4 h. The application of these tests to a collection of 633 strains of Enterobacteriaceae and Vibrionaceae demonstrates that some of the tests may be valuable additions to the present tests available for the identification of bacteria belonging to these families. beta-glucuronidase activity was observed only in strains of the Escherichia-Shigella group. 97 per cent of the Escherichia strains possessed beta-glucuronidase activity. beta-xylosidase activity was almost completely restricted to strains of the Klebsiella-Enterobacter group in addition to Yersinia strains. None of the strains possessed alpha-fucosidase activity.
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PMID:Rapid diagnosis of Enterobacteriaceae. I. Detection of bacterial glycosidases. 0 74

Bacteriophages (phi) have been used to degrade polysaccharides into oligosaccharides containing one or more of their repeating units. The capsular polysaccharide from Klebsiella K44 contains an acetate group, and n.m.r. spectroscopy and chemical methods have been employed to prove its linkage to O-6 of the 4-linked glucose residue. Phage phi 44 was shown to be an alpha-glucosidase not influenced by the acetate moiety and thus able to depolymerize the polysaccharide into pentasaccharide repeating units, some of which contained acetate on O-6 of the reducing glucose residue. The two oligosaccharides were studied by 1H- and 13C-n.m.r. spectroscopy, and their spectra were compared with those of the native and the deacetylated polysaccharide. 13C-n.m.r. was a useful tool for locating the 6-linked acetate, the position of which was confirmed by the method of temporary protection using methyl vinyl ether. The importance of using bacteriophages to obtain oligosaccharides is highlighted by the better results obtained with the oligosaccharide in comparison to the polysaccharide, both in n.m.r. spectroscopy and the temporary protection method.
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PMID:Bacteriophage degradation of Klebsiella K44 polysaccharide: an n.m.r. study and chemical proof of the position of the acetate group. 402 44

1. Pullulanase synthesis was studied in 16 classified (N.C.I.B.) strains and in an industrial strain (R) of Klebsiella aerogenes grown in chemostats containing maltose as inducer and sole carbon source. 2. Maximum synthesis was associated with carbon-limited growth at a low dilution rate (about 0.2h(-1)). The enzyme remained firmly cell-bound and seemed to be located on the cell surface. 3. Three strains had high activity (R, N.C.I.B. 5938, 8017), twelve were intermediate, and two (N.C.I.B. 8153, 9146) had negligible activity but were inducible with pullulan. 4. Pullulan similarly induced low, but adequate, activity in the other strains in conditions (nutrient limitation other than carbon-limitation) in which pullulanase was otherwise very seriously repressed. Nevertheless, in carbon limitation pullulan induced no more enzyme than did maltose, maltotriose or oligosaccharide mixtures, and ;hyperactivity' never developed on protracted culture. 5. Cyclic AMP relieved the transient repression produced by adding glucose to maltose-limited cultures and a further change to glucose-limited conditions led to constitutive pullulanase synthesis. 6. Amylomaltase and alpha-glucosidase activities were also examined but in less detail. 7. The presence of pullulanase in maltose-limited growth is discussed, but no clear function can be assigned to it at present. The molar growth yields for all the strains were very similar, and no correlation was found between the overgrowth of one strain by another and pullulanase activity. Further, any function as a general branching enzyme in polysaccharide synthesis seems unlikely.
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PMID:Pullulanase synthesis in klebsiella (aerobacter) aerogenes strains growing in continuous culture. 437 62

Klebsiella pneumoniae is presently unique among bacterial species in its ability to metabolize not only sucrose but also its five linkage-isomeric alpha-d-glucosyl-d-fructoses: trehalulose, turanose, maltulose, leucrose, and palatinose. Growth on the isomeric compounds induced a protein of molecular mass approximately 50 kDa that was not present in sucrose-grown cells and which we have identified as an NAD(+) and metal ion-dependent 6-phospho-alpha-glucosidase (AglB). The aglB gene has been cloned and sequenced, and AglB (M(r) = 49,256) has been purified from a high expression system using the chromogenic p-nitrophenyl alpha-glucopyranoside 6-phosphate as substrate. Phospho-alpha-glucosidase catalyzed the hydrolysis of a wide variety of 6-phospho-alpha-glucosides including maltose-6'-phosphate, maltitol-6-phosphate, isomaltose-6'-phosphate, and all five 6'-phosphorylated isomers of sucrose (K(m) approximately 1-5 mm) yet did not hydrolyze sucrose-6-phosphate. By contrast, purified sucrose-6-phosphate hydrolase (M(r) approximately 53,000) hydrolyzed only sucrose-6-phosphate (K(m) approximately 80 microm). Differences in molecular shape and lipophilicity potential between sucrose and its isomers may be important determinants for substrate discrimination by the two phosphoglucosyl hydrolases. Phospho-alpha-glucosidase and sucrose-6-phosphate hydrolase exhibit no significant homology, and by sequence-based alignment, the two enzymes are assigned to Families 4 and 32, respectively, of the glycosyl hydrolase superfamily. The phospho-alpha-glucosidase gene (aglB) lies adjacent to a second gene (aglA), which encodes an EII(CB) component of the phosphoenolpyruvate-dependent sugar:phosphotransferase system. We suggest that the products of the two genes facilitate the phosphorylative translocation and subsequent hydrolysis of the five alpha-d-glucosyl-d-fructoses by K. pneumoniae.
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PMID:Metabolism of sucrose and its five linkage-isomeric alpha-D-glucosyl-D-fructoses by Klebsiella pneumoniae. Participation and properties of sucrose-6-phosphate hydrolase and phospho-alpha-glucosidase. 1147 29