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)

Folding and assembly into complexes of some viral glycoproteins are exquisitely sensitive to endoplasmic reticulum (ER) alpha-glucosidase inhibition, which prevents the trimming of glucose from N-linked glycans. Derivatives of deoxynojirimycin (DNJ) iminosugars, which are potent alpha-glucosidase inhibitors, were shown to have antiviral activity against bovine viral diarrhea virus, a pestivirus related to hepatitis C virus (HCV). The aim of this study was to determine whether these inhibitors would affect HCV infectivity and to provide novel insights on their mechanism of action. The overall antiviral activity of glucosidase inhibitors was shown by using the two most relevant models currently available: the cell-culture model enabling complete replication of the HCV JFH1 strain in Huh7.5 cells, and infectious HCV pseudotyped particles (HCVpp) produced in HEK-293T cells that display functional E1-E2 glycoprotein complexes. By using the latter model, it is shown that the inhibition of alpha-glucosidases by iminosugars results in the misfolding and misassembly of HCV glycoprotein pre-budding complexes. This inhibition of the assembly of E1-E2 in the ER of transfected HEK-293T cells leads to a reduction in the incorporation of E1-E2 complexes into HCVpp. More importantly, it is demonstrated that the infectivity of HCVpp that are released under treatment is reduced and that this reduction in infectivity is due to the incorporation of misfolded envelope glycoproteins in secreted particles. These properties suggest the potential usefulness of DNJ derivatives in combating HCV infection.
...
PMID:Reduction of the infectivity of hepatitis C virus pseudoparticles by incorporation of misfolded glycoproteins induced by glucosidase inhibitors. 1737 56

Andrographolide (1), the cytotoxic agent of the plant Andrographis paniculata, was subjected to semi-synthetic studies leading to a series of new derivatives, a novel family of glucosidase inhibitors. Nicotination of 3,19-hydroxyls in 15-alkylidene andrographolide derivatives (9) was favorable to alpha-glucosidase inhibition activity. Among them, 15-p-chlorobenzylidene-14-deoxy-11,12-didehydro-3,19-dinicotinateandrographolide (11c) was a very potent inhibitor against alpha-glucosidase with an IC50 value of 6 microM. However, all compounds concerned for beta-glucosidase showed no inhibition. All compounds synthesized were characterized by the analysis of NMR, IR, HRMS spectra and the stereochemistry of 2 was confirmed by X-ray analysis.
...
PMID:Synthesis of andrographolide derivatives: a new family of alpha-glucosidase inhibitors. 1742 67

The syntheses of polyhydroxylated imino- and anhydro thio-alditol compounds related to the naturally occurring glycosidase inhibitor, salacinol, containing a phosphate group in the side chain are described. The compounds lack hydroxyl groups on the acyclic side chain and are prototypes of the exact salacinol analogue. The synthetic strategy relies on the Mitsunobu reaction of N- and S-hydroxyalkyl derivatives of 2,3,5-tri-O-benzyl-1,4-dideoxy-1,4-imino-D-arabinitol and 1,4-anhydro-2,3,5-tri-O-benzyl-1-thio-D-arabinitol with dibenzyl phosphate to yield the corresponding protected heteroalditol phosphates. Screening of these compounds against recombinant human maltase glucoamylase (MGA), a critical intestinal glucosidase involved in the processing of oligosaccharides of glucose into glucose itself, shows that they are not effective inhibitors of MGA and demonstrates the importance of the hydroxyl and/or sulfate substituents present on the side chain for effective inhibition. The attempted synthesis of the exact analogue of salacinol by opening of cyclic phosphates is also described.
...
PMID:Synthesis of phosphate derivatives related to the glycosidase inhibitor salacinol. 1757 96

Six heteroanalogues (X = S, Se, NH) of the naturally occurring glucosidase inhibitor salacinol, containing polyhydroxylated, acyclic chains of 6-carbons, were synthesized for structure-activity studies with different glycosidase enzymes. The target zwitterionic compounds were synthesized by means of nucleophilic attack of the PMB-protected 1,4-anhydro-4-seleno-, 1,4-anhydro-4-thio-, and 1,4-anhydro-4-imino-D-arabinitols at the least hindered carbon atom of 1,3-cyclic sulfates. These 1,3-cyclic sulfates were derived from D-glucose and D-galactose, and significantly, they utilized butane diacetal as the protecting groups for the trans 2,3-diequatorial positions. Deprotection of the coupled products proceeded smoothly, unlike in previous attempts with different protecting groups, and afforded the target selenonium, sulfonium, and ammonium sulfates with different stereochemistry at the stereogenic centers. The four new heterosubstituted compounds (X = Se, NH) inhibited recombinant human maltase glucoamylase (MGA), one of the key intestinal enzymes involved in the breakdown of glucose oligosaccharides in the small intestine. The two selenium derivatives each had Ki values of 0.10 microM, giving the most active compounds to date in this general series of zwitterionic glycosidase inhibitors. The two nitrogen compounds also inhibited MGA but were less active, with Ki values of 0.8 and 35 microM. The compounds in which X = S showed Ki values of 0.25 and 0.17 microM. Comparison of these data with those reported previously for related compounds reinforces the requirements for an effective inhibitor of MGA. With respect to chain extension, the configurations at C-2' and C-4' are critical for activity, the configuration at C-3', bearing the sulfate moiety, being unimportant. It would also appear that the configuration at C-5' is important but the relationship is dependent on the heteroatom.
...
PMID:New synthetic routes to chain-extended selenium, sulfur, and nitrogen analogues of the naturally occurring glucosidase inhibitor salacinol and their inhibitory activities against recombinant human maltase glucoamylase. 1765 54

The prevention and treatment of non-communicable diseases by using the beneficial biological effects of polyphenolic plants have attracted increasing interest from nutritional scientists. The a-glucosidase inhibitory and antioxidant activities of aqueous and methanolic extracts from 28 common Vietnamese edible plants, comprising 4 groups (plants used for making drinks, edible wild vegetables, herbs, and dark green vegetables), were investigated in vitro. The polyphenol contents of these extracts were determined by the Folin-Ciocalteu method and calculated as catechin equivalents. The extracts from plants used for making drinks showed the highest activities for both a-glucosidase inhibition and as antioxidants, followed by edible wild vegetables, herbs, and dark green vegetables. Positive relationships among alpha-glucosidase inhibitory activities, antioxidant activities and polyphenol contents of these 28 edible plants were found in both aqueous and methanolic extracts. Four new promising materials that are similar to or better than guava leaf extract, including Syzygium zeylanicum, Cleistocalyx operculatus, Horsfieldia amygdalina and Careya arborea demonstrated high alpha-glucosidase inhibitory activity (93, 76, 68 and 67%, respectively) at the final concentration of 0.8 mg lyophilized material/mL solution and antioxidant activity (85, 87, 78 and 80%, respectively) at the final concentration of 30 pg lyophilized material/mL solution. These four edible plants contained significantly high polyphenol contents (equivalent to 251.7, 146.6, 136.6 and 168.6 mg of catechin/g dry weight, respectively). Thus, these four materials might be possible new sources of a-glucosidase inhibition and antioxidants suitable for use as functional foods in the future.
...
PMID:Alpha-glucosidase inhibitory and antioxidant activities of Vietnamese edible plants and their relationships with polyphenol contents. 1787 33

We have proven that xanthones 1-8 isolated from the root of C. tricuspidata possess highly potent alphaalpha-glucosidase inhibition properties. Compound 1 was identified as a new isoprenylated tetrahydroxy xanthone, 1,3,6,7-tetrahydroxy-2-(3-methylbut-2-enyl)-8-(2-methylbut-3-en-2-yl)-9H-xanthen-9-one (1). These are the first natural xanthones documented to exhibit such inhibition. The IC(50) values of compounds 1-8 inhibiting alpha-glucosidase activity were determined to be up to 16.2microM. Mechanistic analysis showed the xanthones 1-8 exhibited full mixed inhibition.
...
PMID:Xanthones from Cudrania tricuspidata displaying potent alpha-glucosidase inhibition. 1795 May 99

A commercial chromogenic agar medium (DFI) was supplemented with glucose (mDFI) to enhance the specificity of Enterobacter sakazakii (E. sakazakii) detection. Escherichia vulneris (E. vulneris), a putative false-positive strain on the DFI medium, produces alpha-glucosidase. The enzyme alpha- glucosidase hydrolyzes a substrate, 5-bromo-4-chloro-3- indolyl-alpha,D-glucopyranoside (XalphaGlc), producing green colonies. E. sakazakii strains produced green colonies on both DFI and mDFI agar, whereas E. vulneris produced green colonies on DFI agar but small white colonies on mDFI agar. E. sakazakii and E. vulneris were also readily differentiated by colony color when the mixed culture of the two strains was plated on mDFI agar and incubated for 24 h at 37 degrees C. The results indicate that the selectivity of the commercial chromogenic agar medium could be improved by a simple supplementation with glucose.
...
PMID:Evaluation of a chromogenic medium supplemented with glucose for detecting Enterobacter sakazakii. 1838 80

The synthesis ofcis- and trans-1,6-dihydroxypyrrolizidine starting fromtrans-4-hydroxyl-L-proline and their evaluation as glycosidase inhibitors are reported. Thecis-isomer was found to be a potent inhibitor against alpha-glucosidase and showed weak inhibitory effect against other glycosidases. Thetrans-isomer exhibited weak inhibitions of b-glucosidase and amyloglucosidase and poor inhibition of other glycosidases.
...
PMID:Synthesis and activity of a potent alpha-glucosidase inhibitor, (1R, 6R, 8S)-cis-1,6-dihydroxypyrrolizidine, and its isomer. 1897 77

The compounds that could inhibit the activity of a-glucosidase are potentially used for antidiabetic by suppressing postprandial hyperglycemia. This research aimed to investigate the hypoglycemic activity in A. terreus koji extracted by ethyl acetate. The extracts was dissolved in methanol: water (1:4), followed by fractionations with n-hexane, methylene chloride and ethyl acetate. Each fraction was assayed for its activity against a-glucosidase. The active fraction was purified by column chromatography using silica gel and resin as adsorbent. The kopi extract showed potential as alpha-glucosidase inhibition with IC50 <10 microg mL(-1) and showed combination of non-competitive and uncompetitive inhibition mode against a-glucosidase. Ethyl acetate fraction showed potential as inhibitor alpha-glucosidase with IC50 = 8.6 microg mL(-1). In animal experiment, active fraction (F10-4) of ethyl acetate fraction suppressed the increase of postprandial blood glucosidase level compare to the control. Thus it showed potential as alpha-glucosidase inhibitor and demonstrated depressed postprandial blood glucose level and may have potential use in the management of type 2 diabetes.
...
PMID:Inhibitory effect of koji Aspergillus terreus on alpha-glucosidase activity and postprandial hyperglycemia. 1909 Jan 11

Fungi are important aeroallergens. However, fungal allergen sources of consistent quality for clinical testing are not readily available. Because some allergens have been identified as enzymes, we assessed the prevalence of IgE reactivity to commercially available fungal enzymes. The purpose of this study was to determine IgE antibody reactivity by radioallergosorbent assay (RAST) to commercially available fungal enzymes in mold-allergic individuals. Sera from 20 subjects with symptoms of respiratory allergies and skin test reactivity to 2 or more fungal allergens (4 conidial [imperfecti] fungi and/or 8 basidiomycetes) were selected. Controls were six atopic individuals with neither history of fungal allergy nor skin test reactivity to fungi. Seventeen commercial fungal enzymes were used as antigens to evaluate the subjects' IgE antibody reactivity by RAST. Sera from most fungus-allergic individuals showed substantial IgE antibody reactivity to enzymes; control sera showed little or no reactivity. The mean reactivity to all commercial enzymes of all subjects tested was RAST > or = 3% with only one exception. The most reactive fungal enzymes were invertase (bakers' yeast, Saccharomyces cerevisiae), cellulase (Trichoderma viride), and glucosidase (brewers yeast, S. cerevisiae) with mean binding of 14.6, 9.5, and 8.8%, respectively. Using RAST results with a combination of four enzymes from S. cerevisiae (brewers yeast glucosidase, bakers' yeast maltase, invertase, and invertase V), a sensitivity of 100% was shown for detecting mold-allergic patients. The studies suggest that fungal enzymes may be useful source materials for the identification of fungal allergens and may also provide readily available source materials to produce improved diagnostic and therapeutic reagents.
...
PMID:Prevalence of IgE reactivities in mold-allergic subjects to commercially available fungal enzymes. 1917 90


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

---