Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GLUCOSIDASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed2003

Inhibitory effect of aqueous extract from the gall of Rhus chinensis on alpha-glucosidase activity and postprandial blood glucose.

The present study examined the inhibitory effect of aqueous extract from the gall of Rhus chinensis (AEGRC) on alpha-glucosidase activity, an enzyme responsible for digestion of carbohydrate to monosaccharides in the process of intestinal absorption. AEGRC inhibited Bacillus alpha-glucosidase acitvity with an IC(50) of 0.9 micro g/ml. Its inhibition on alpha-glucosidase was determined to be noncompetitive and reversible when the enzyme-substrate mixture was simultaneously treated with AEGRC as an inhibitor. In addition, when it was orally administered to rats with sucrose (2g/kg), AEGRC (250-1000mg/kg) significantly suppressed the increase of blood glucose levels after sucrose loading in a dose dependent manner. These results suggest that AEGRC might exert anti-diabetic effect by suppressing carbohydrate absorption from intestine, and thereby reducing the postprandial increase of blood glucose.

Animals↗
PubMed1999

Subsite affinities of beta-glucosidase from Aspergillus sojae on various xylooligosaccharides.

The subsite affinities of beta-glucosidase (EC 3.2.1.21) with high beta-xylosidase activity from Aspergillus sojae on various xylooligosaccharides (degree of polymerization: n = 2-6) were investigated by steady-state kinetic analysis. The molecular activity (k0) value of the enzyme for xylobiose was not markedly different from those of other substrates (n = 3-6). The arrangement of the subsite affinities (A(i), i = 1-6) was evaluated; A1 = 2.93 kcal/mol, A2 = 3.67 kcal/mol, A3 = 0.64 kcal/mol, A4 = 0.12 kcal/mol, A5 = -0.07 kcal/mol, A6 = -0.05 kcal/mol, and the intrinsic rate constant (K(int)) was 7.6 s(-1). The subsite structure was similar to those of beta-glucosidase from A. niger and alpha-glucosidases from A. niger and Mucor javanicus, where the values for A1 were much larger than those for A3.

Journal Article↗
PubMed2005

Cuminaldehyde: Aldose Reductase and alpha-Glucosidase Inhibitor Derived from Cuminum cyminum L. Seeds.

The inhibitory activity of Cuminum cyminum seed-isolated component was evaluated against lens aldose reductase and alpha-glucosidase isolated from Sprague-Dawley male rats and compared to that of 11 commercially available components derived from C. cyminum seed oil, as well as quercitrin as an aldose reductase inhibitor and acarbose as an alpha-glucosidase inhibitor. The biologically active constituent of C. cyminum seed oil was characterized as cuminaldehyde by various spectral analyses. The IC(50) value of cuminaldehyde is 0.00085 mg/mL against aldose reductase and 0.5 mg/mL against alpha-glucosidase, respectively. Cuminaldehyde was about 1.8 and 1.6 times less in inhibitory activity than acarbose and quercitin, respectively. Nonetheless, cuminaldehyde may be useful as a lead compound and a new agent for antidiabetic therapeutics.

Aldehyde Reductase↗
PubMed2001

Subcellular localization of beta-glucosidase in rye, maize and wheat seedlings.

The subcellular compartmentation of beta-glucosidase was studied in rye, maize and wheat seedlings by immunocytochemical methods. For detection, we used a 10 nm gold-labeled secondary antibody, and results were observed using transmission electron microscopy. In all three species, beta-glucosidase was found in plastids, cytoplasm and cell walls. In rye, gold particles were seen on cell walls and cytoplasm in epidermal cells of the root tip and shoot, in bundle sheath cells of the shoot and in all cells, except the vascular bundle cells of the coleoptile. Gold labeling was also observed in plastids of the bundle sheath cells of rye shoot tips and in cortical cells of root tips. In wheat, gold labeling was observed on cell walls and cytoplasm of epidermal cells in the shoot base and coleoptile, and on cell walls and plastids in epidermal cells of the root tip. In maize, gold labeling was mainly found in plastids or proplastids in vascular bundle cells and bundle sheath cells of the shoot, in bundle sheath cells of the coleoptile and in epidermal cells of the root. Some gold particles were also found in cell walls and cytoplasm of stomatal guard cells of the shoot base and vascular bundle cells of the shoot tip and in the cell walls of bundle sheath cells of the shoot tip and root tip epidermal cells. Results are discussed in relation to the role of beta-glucosidase in hydroxamic acid release and overall defense mechanism of monocotyledons.

Journal Article↗
PubMed1967

Metabolism of the reserve polysaccharide of Streptococcus mitis. Properties of alpha-(1-->6)-glucosidase, its separation from transglucosylase, and the action of the two enzymes on branched oligosaccharides.

1. An alpha-(1-->6)-glucosidase has been separated from cell extracts of Streptococcus mitis. The enzyme was freed from transglucosylase by adsorption of the latter on retrograded amylose. 2. The enzyme was detected in five of the six strains of S. mitis that were studied; alpha-(1-->6)-glucosidase was not found in strain RB1633, a strain that did not store polysaccharide. 3. The glucosidase could act on compounds in which alpha-glucose is joined through an alpha-(1-->6)-bond to either a maltosaccharide or an isomaltosaccharide. 6(2)-alpha-Glucosylmaltose (panose) and 6(3)-alpha-glucosylmaltotriose were hydrolysed more rapidly and isomaltodextrins more slowly than isomaltose. 4. Transferring activity towards isomaltose and panose was appreciable when the concentration of substrate was 2% or higher. 5. The enzyme had no action on alpha-(1-->4)-glucosidic linkages. 6-alpha-Maltodextrinylglucoses were hydrolysed only after transglucosylase action had attenuated them to isomaltose.

Journal Article↗
PubMed1996

Functional organization of saposin C. Definition of the neurotrophic and acid beta-glucosidase activation regions.

Saposin C is an essential co-factor for the hydrolysis of glucosylceramide by acid beta-glucosidase in mammals. In addition, prosaposin promotes neurite outgrowth in vitro via sequences in saposin C. The regional organization of these neurotrophic and activation properties of saposin C was elucidated using recombinant or chemically synthesized saposin Cs from various regions of the molecule. Unreduced and reduced proteins were analyzed by electrospray-mass spectrometry to establish the complement of disulfide bonds in selected saposin Cs. Using saposin B as a unreactive backbone, chimeric saposins containing various length segments of saposin B and C localized the neurotrophic and acid beta-glucosidase activation properties to the carboxyl- and NH2-terminal 50% of saposin C, respectively. The peptide spanning residues 22-31 had neurotrophic effects. Molecular modeling and site-directed mutagenesis localized the activation properties of saposin C to the region spanning residues 47-62. Secondary structure was needed for retention of this property. Single substitutions of R and S at the conserved cysteines at 47 or 78 diminished but did not obliterate the activation properties. These results indicate the segregation of neurotrophic and activation properties of saposin C to two different faces of the molecule and suggest a topographic sequestration of the activation region of prosaposin for protection of the cell from adverse hydrolytic activity of acid beta-glucosidase.

Amino Acid Sequence↗
PubMed2006

Molecular and structural characterization of hexameric beta-D-glucosidases in wheat and rye.

The wheat (Triticum aestivum) and rye (Secale cereale) beta-D-glucosidases hydrolyze hydroxamic acid-glucose conjugates, exist as different types of isozyme, and function as oligomers. In this study, three cDNAs encoding beta-D-glucosidases (TaGlu1a, TaGlu1b, and TaGlu1c) were isolated from young wheat shoots. Although the TaGlu1s share very high sequence homology, the mRNA level of Taglu1c was much lower than the other two genes in 48- and 96-h-old wheat shoots. The expression ratio of each gene was different between two wheat cultivars. Recombinant TaGlu1b expressed in Escherichia coli was electrophoretically distinct fromTaGlu1a and TaGlu1c. Furthermore, coexpression of TaGlu1a and TaGlu1b gave seven bands on a native-PAGE gel, indicating the formation of both homo- and heterohexamers. One distinctive property of the wheat and rye glucosidases is that they function as hexamers but lose activity when dissociated into smaller oligomers or monomers. The crystal structure of hexameric TaGlu1b was determined at a resolution of 1.8 A. The N-terminal region was located at the dimer-dimer interface and plays a crucial role in hexamer formation. Mutational analyses revealed that the aromatic side chain at position 378, which is located at the entrance to the catalytic center, plays an important role in substrate binding. Additionally, serine-464 and leucine-465 of TaGlu1a were shown to be critical in the relative specificity for DIMBOA-glucose (2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one) over DIBOA-glucose (7-demethoxy-DIMBOA-glucose).

Amino Acid Sequence↗
PubMed1974

Evidence Against the Involvement of Galactosidase or Glucosidase in Auxin- or Acid-stimulated Growth.

Research on the mode of action of auxin in the promotion of growth has shown that auxin treatment leads to hydrogen ion secretion and wall acidification. It has recently been reported that auxin stimulates cell wall beta-galactosidase activity in Avena coleoptiles, presumably by causing cell wall acidification, since the pH optimum for the enzyme is about 5.0. It has been suggested that enhancement of beta-galactosidase and/or other glycosidase activity mediates growth promotion by auxin or low pH. This hypothesis was tested by examining the effect of inhibitors of beta-galactosidase and beta-glucosidase. Severe inhibition of measureable beta-galactosidase or beta-glucosidase activity was found to have no effect on auxin- or acid-promoted growth. It is concluded that neither beta-galactosidase nor beta-glucosidase plays an important role in short term growth promotion by auxin or acid. The data do not rule out the possibility that some other cell wall glycosidase is involved in auxin or acid action.

Journal Article↗
PubMed1981

Subcellular Localization of Dhurrin beta-Glucosidase and Hydroxynitrile Lyase in the Mesophyll Cells of Sorghum Leaf Blades.

Studies with purified mesophyll and epidermal protoplasts and bundle sheath strands have shown that the cyanogenic glucoside dhurrin (p-hydroxy-(S)-mandelonitrile-beta-d-glucoside) is localized in the epidermis of sorghum leaves whereas the enzymes involved in its degradation (dhurrin beta-glucosidase and hydroxynitrile lyase) are localized in the mesophyll tissue (Kojima M, JE Poulton, SS Thayer, EE Conn 1979 Plant Physiol 63: 1022-1028). The subcellular localization of these enzymes has now been examined using linear 30 to 55% (w/w) sucrose gradients by fractionation of mesophyll protoplast components. The hydroxynitrile lyase is found in the supernatant fractions suggesting a cytoplasmic (soluble cytoplasm, microsomal or vacuolar location). The dhurrin beta-glucosidase (dhurrinase) is particulate and mostly chloroplast-associated. The dhurrinase activity peak has a shoulder of activity more dense than that of the intact chloroplasts. This shoulder does not coincide with markers of any other cell fraction.In studies of chloroplasts isolated from ruptured mesophyll protoplasts by differential, low-speed centrifugation, the dhurrinase partitions in the same manner as the chloroplast marker triose phosphate dehydrogenase. Chloroplast localization of the beta-glucosidase has also been shown in histochemical studies using 6-bromo-2-naphthyl-beta-d-glucoside substrate coupled with fast Blue B.

Journal Article↗
PubMed1988

Effects of prolonged administration of two new alpha-glucosidase inhibitors on blood glucose control, insulin requirements and breath hydrogen excretion in patients with insulin-dependent diabetes mellitus.

Alpha-glucosidase inhibitors delay carbohydrate absorption. In order to study the effects of two new alpha-glucosidase inhibitors with long (BAYo1248) and short (BAYm1099) duration of action on glycaemic control, seventeen insulin-dependent diabetics were connected to the Biostator for 24 h and postprandial hyperglycaemia, insulin requirements and breath H2 concentrations were assessed under three conditions: (a) before administration of any alpha-glucosidase inhibitor (control experiments), (b) after administration of BAYo1248 (40 mg before breakfast, nine patients) or BAYm1099 (100 mg before breakfast and dinner, eight patients) for 1 month, (c) after 1-month administration of placebo (double-blind crossover study). All patients were on standard diets (30 kcal kg-1, 45% carbohydrate, 35% fat, 20% protein). BAYo1248 reduced postprandial hyperglycaemia and insulin requirements (vs. values in control and placebo experiments) after breakfast (124 +/- 8 vs. 159 +/- 8 and 158 +/- 8 mg dl-1, 16 +/- 2 vs. 24 +/- 4 and 23 +/- 3 units, P less than 0.01) and lunch (138 +/- 7 vs. 155 +/- 11 and 162 +/- 13 mg dl-1, 19 +/- 3 vs. 24 +/- 3 and 23 +/- 3 units, P less than 0.01) whereas BAYm1099 reduced postprandial hyperglycaemia and insulin requirements after breakfast (127 +/- 4 vs. 167 +/- 12 and 159 +/- 6 mg dl-1, 15 +/- 3 vs. 24 +/- 4 and 21 +/- 3 units, P less than 0.02) and dinner (128 +/- 4 vs. 169 +/- 7 and 157 +/- 10 mg dl-1, 19 +/- 2 vs. 28 +/- 3 and 25 +/- 2 units, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

1-Deoxynojirimycin↗
PubMed1994

Intestinal effects of alpha-glucosidase inhibitors: absorption of nutrients and enterohormonal changes.

The present paper addresses the question how alpha-glucosidase inhibitors affect glucose homeostasis. To facilitate this already established data on the effects of induced malabsorption on gut hormones such as gastric inhibitory polypeptide (GIP) in connection with preliminary findings which deal with the new incretin hormone glucagon-like peptide 1 (7-36) amide (GLP-1) are discussed. To emphasize the possibly important impact of a regulated GLP-1 release in response to glucosidase inhibitor treatment we evaluate the recently introduced concept of 'glucose competence' of pancreatic beta-cells. The slowing of nutrient (i.e. glucose) absorption by therapeutic means (for example, acarbose) could supplement a new approach in the treatment of type 2 diabetics which would utilize the well-preserved insulinotropic activity of GLP-1 in these patients, its glucagon-lowering effect, and its possible inhibition of gastric emptying rates, the latter helping to reduce the requirement for rapid insulin secretory responses as is intended while using alpha-glucosidase inhibitor treatment.

Animals↗
PubMed1995

Cleavage of trehalose-phosphate in Bacillus subtilis is catalysed by a phospho-alpha-(1-1)-glucosidase encoded by the treA gene.

A 2.5 kb DNA fragment contain a gene encoding a phospho-alpha-(1-1)-glucosidase (phosphotrehalase), designated treA, was isolated from a Bacillus subtilis chromosomal library by complementation of the tre-12 mutation. The major TreA activity was found in the cytoplasm. TreA exhibits high sequence similarity to thermostable oligo 1,6 beta-glucosidases of several species and the trehalose-6-phosphate hydrolase TreC of Escherichia coli. TreA activity is induced by trehalose and repressed by glucose, fructose or mannitol. Induction by trehalose and repression by glucose are concentration dependent. The highest activity of TreA occurs 90 min before the end of the exponential growth phase in crude cell extracts. The enzyme is able to cleave para-nitrophenyl-glucopyranoside and trehalose-6-phosphate but not trehalose. These results indicate that treA encodes a specific phospho-alpha-(1-1)-glucosidase which cleaves trehalose-6-phosphate in the cytoplasm after transport and phosphorylation of trehalose. The 5' flanking region of treA contains an open reading frame which was partially sequenced, whose product shows about 40% identity to sucrose Enzyme II of the phosphotransferase transport system from several organisms.

Amino Acid Sequence↗
PubMed1994

Inhibition of alpha-glucosidase I of the glycoprotein-processing enzymes by 6-O-butanoyl castanospermine (MDL 28,574) and its consequences in human immunodeficiency virus-infected T cells.

The 6-O-butanoyl derivative of castanospermine (MDL 28,574) was previously shown to be approximately 30-fold more potent than the naturally occurring molecule at inhibiting the replication of human immunodeficiency virus (HIV) (D. L. Taylor, P. S. Sunkara, P. S. Liu, M. S. Kang, T. L. Bowlin, and A. S. Tyms, AIDS 5:693-698, 1991). We now report that consistent with its improved anti-HIV activity, MDL 28,574 is more effective (50% inhibitory concentration [IC50], 20 microM) than the parent molecule (IC50, 254 microM) at causing the accumulation of glucosylated oligosaccharides in HIV-infected cells by inhibition of glycoprotein processing. These were predominantly of the glucose 3 type, as determined by P4 Bio-Gel analysis after digestion with purified alpha-glucosidase I, indicating that, intracellularly, this enzyme is the major target for inhibition. MDL 28,574, however, was less active (IC50, 1.27 microM) than castanospermine (IC50, 0.12 microM) against the mutual target enzyme, cellular alpha-glucosidase I, in a cell-free assay system. The increased effects of MDL 28,574 against alpha-glucosidase I in cell culture were attributed to the improved cellular uptake of the more lipophilic derivative. Inhibition of this enzyme activity in HIV-infected H9 cells impaired viral glycoprotein processing and resulted in the expression of abnormally configured gp120. This did not affect virus production, but the virions had decreased infectivity which was partially related to a reduced ability to bind to CD4+ T cells.

Antiviral Agents↗
PubMed1981

Formation and Location of 1,4-beta-Glucanases and 1,4-beta-Glucosidases from Penicillium janthinellum.

Formation and location of 1,4-beta-glucanases and 1,4-beta-glucosidases were studied in cultures of Penicillium janthinellum grown on Avicel, sodium carboxymethyl cellulose, cellobiose, glucose, mannose, and maltose. Endo-1,4-beta-glucanases were found to be cell free, and their formation was induced by cellobiose. 1,4-beta-Glucosidases, on the other hand, were formed constitutively and were primarily cell free, but with a small amount strongly associated with the cell wall. Low 1,4-beta-glucosidase activities of periplasmic or intracellular origin were also found. A rotational viscosimetric method was developed to measure the total endo-1,4-beta-glucanase activity of the culture (broth and solids). By this method, it was possible to determine the endo-1,4-beta-glucanase activity not only in the supernatant of the culture but also on the surface of the mycelium or absorbed on residual Avicel. During a 70-liter batch cultivation of P. janthinellum, the adsorption of endo-1,4-beta-glucanases by residual and newly added 10% Avicel was measured. The adsorption of soluble protein and endo-1,4-beta-glucanases by Avicel was found to be largely independent of the pH value but dependent on temperature.

Journal Article↗
PubMed1982

Selective Isolation of Fusarium graminearum Mutants Derepressed for Production of beta-Glucosidase.

A strain of Fusarium graminearum produced extracellular beta-glucosidase (beta-d-glucoside glucohydrolase [EC 3.2.1.21]) subject to carbon catabolite repression. Derepressed mutants were selectively isolated by the use of 2-deoxyglucose, a nonmetabolizable catabolic repressor. On each plate of cellobiose and 2-deoxy-glucose inoculated with 10 spores and irradiated with UV light, a few colonies emerged. Comparative growth experiments with one of the derepressed mutants and the parent strain showed that the mutant produced beta-glucosidase in the presence of glucose. Furthermore, the same mutant produced more beta-glucosidase than did the wild-type strain on cellobiose alone.

Journal Article↗
PubMed1983

Comparison of beta-Glucosidase Activities in Different Streptomyces Strains.

Cellobiase (beta-glucosidase) production was compared for two streptomycetes: Streptomyces flavogriseus, a known producer of cellulase complex, and Streptomyces sp. strain CB-12, a strain isolated for its rapid growth on cellobiose. The optimal conditions for enzyme activity were established in relation to pH, temperature, enzyme stability, and substrate affinity. The production of beta-glucosidase by the two strains depended on the carbon substrate in the medium. Cellobiose was found to repress the biosynthesis of the enzyme in S. flavogriseus and to stimulate its production in strain CB-12. The biosynthesis of the enzyme correlated well with the accumulation of glucose in the culture filtrates. The combined action of the beta-glucosidases produced by the two Streptomyces strains might allow a better utilization of the reaction products which arise during the biodegradation of cellulose.

Journal Article↗
PubMed1988

Induction and Catabolite Repression of beta-Glucosidase Synthesis in Myceliophthora thermophila D-14 (= ATCC 48104).

beta-Glucosidase activity in Myceliophthora thermophila D-14 (= ATCC 48104) was inducible and was produced in culture filtrate during growth with various inducers, of which PNPG (p-nitrophenyl-beta-d-glucoside) was the most efficient. Induction of beta-glucosidase also occurred when the organism was grown in medium supplemented with different carbon sources. Carboxymethyl cellulose, cellobiose, and Solka-Floc were found effective for induction of enzyme biosynthesis. The addition of glucose to the culture medium severely repressed beta-glucosidase synthesis, which could not be reversed by exogenous cyclic AMP or dibutyryl cyclic AMP.

Journal Article↗