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)

A diketopiperazine (1) has been isolated from the culture broth of Penicillium sp. F70614 and its structure has been determined to be cyclo(dehydroala-L-Leu) by various spectroscopic analyses. This compound selectively inhibited yeast alpha-glucosidase and porcine intestinal alpha-glucosidase with IC50 values of 35 and 50 microg/ml, respectively. However, it did not show significant inhibitory effects against almond beta3-glucosidase, Aspergillus alpha-galactosidase, Escherichia coli beta-galactosidase and jack bean alpha-mannosidase.
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PMID:Cyclo(dehydroala-L-Leu), an alpha-glucosidase inhibitor from Penicillium sp. F70614. 1109 29

The Hansenula polymorpha maltase structural gene (HPMAL1) was isolated from a genomic library by hybridization of the library clones with maltase-specific gene probe. An open reading frame of 1695 nt encoding a 564 amino-acid protein with calculated molecular weight of 65.3 kD was characterized in the genomic DNA insert of the plasmid p51. The protein sequence deduced from the HPMAL1 exhibited 58 and 47% identity with maltases from Candida albicans and Saccharomyces carlsbergesis encoded by CAMAL2 and MAL62, respectively, and 44% identity with oligo-alpha-1,6-glucosidase from Bacillus cereus. The recombinant Hansenula polymorpha maltase produced in Escherichia coli hydrolyzed p-nitrophenyl-alpha-D-glucopyranoside (PNPG), sucrose, maltose and alpha-methylglucoside and did not act on melibiose, cellobiose, trehalose and o-nitrophenyl-beta-D-galactopyranoside (ONPG). The affinity of the recombinant enzyme for its substrates increased in the order maltose <alpha-methylglucoside <sucrose <PNPG. Southern analysis revealed presence of a single maltase gene in H. polymorpha. This is the first report on the maltase gene sequence from a methylotrophic yeast.
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PMID:Cloning of maltase gene from a methylotrophic yeast, Hansenula polymorpha. 1125 10

N-methyl-1-deoxynojirimycin (NMDN), an a-glucosidase inhibitor, reduces myocardial infarct size by reducing the glycogenolytic rate through inhibition of the alpha-1,6-glucosidase of glycogen-debranching enzyme in the heart, in addition to possessing an antihyperglycemic action by blocking alpha-1,4-glucosidase in the intestine. Ischemic preconditioning (PC), which markedly reduces the size of the myocardial infarct, is known to reduce the activity of phosphorylase and reduce the glycogenolytic rate. Therefore, it was hypothesized that a combination of pharmacological inhibition of glycogenolysis by an alpha-1,6-glucosidase inhibitor, NMDN, and PC could markedly reduce myocardial infarct size more than NMDN or PC alone. Japanese white rabbits without collateral circulation were subjected to a 30-min coronary occlusion followed by 48-h reperfusion. The infarct sizes as a percentage of area at risk were significantly reduced by pre-ischemic treatment with either 100mg/kg of NMDN or PC of 5 min ischemia and 5 min reperfusion alone (15.9+/-2.0%, n=8, and 10.3+/-1.2%, n=8, respectively) as compared with the control (43.9+/-2.2%, n=8). However, the combination of 100mg/kg of NMDN and PC significantly reduced the infarct size (4.9+/-1.2, n=8) compared with NMDN or PC alone. Another 40 rabbits, also given 100mg of NMDN, PC, NMDN+PC or saline before ischemia (n=10 in each group), were killed for biochemical analysis after 30 min of ischemia. NMDN and PC preserved the glycogen content and attenuated the lactate accumulation, respectively, as compared with the control. However, the combination of NMDN and PC preserved significantly more glycogen and significantly reduced lactate accumulation than either NMDN or PC alone. The combination of NMDN and PC markedly reduced the myocardial infarct size more than either process alone. The marked preservation of glycogen and marked attenuation of lactate accumulation by the combination of NMDN and PC suggest that the mechanism for this effect of NMDN+PC is related to the inhibition of glycogenolysis.
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PMID:Combination of N-methyl-1-deoxynojirimycin and ischemic preconditioning markedly reduces the size of myocardial infarcts in rabbits. 1144 4

The anti-diabetic drug miglitol, an alpha-glucosidase inhibitor, which is currently used clinically, reduces myocardial infarct size by reducing the glycogenolytic rate through inhibition of the alpha-1,6-glucosidase of glycogen-debranching enzyme in the heart. Nicorandil, a K(ATP) channel opener with a nitrate-like effect, which is also currently used clinically, also reduces the infarct size. Therefore, we hypothesized that combination of nicorandil and submaximal dose of miglitol could markedly reduce myocardial infarct size more than miglitol or nicorandil alone, and investigated the mechanism for the infarct size-reducing effect. Japanese white rabbits without collateral circulation were subjected to 30 min coronary occlusion followed by 48 h reperfusion. Pre-ischaemic treatment with submaximal dose of miglitol (5 mg kg(-1), i.v.) and nicorandil alone (100 microg kg(-1) min(-1) 5 min) moderately reduced the infarct size as a percentage of area at risk (24+/-4 and 25+/-4%, respectively), and 10 mg kg(-1) of miglitol markedly reduced the infarct size (15+/-2%) compared with the controls (42+/-2%). Combination of 5 mg kg(-1) of miglitol and nicorandil (100 microg kg(-1) min(-1) 5 min), and 10 mg kg(-1) of miglitol and nicorandil (100 microg kg(-1) min(-1) 5 min) significantly reduced the infarct size (13+/-4 and 12+/-3%, respectively) more than miglitol or nicorandil alone. Pretreatment with 5HD completely abolished the infarct size-reducing effect of 10 mg kg(-1) of miglitol alone (36+/-7%) and that of combination of 5 mg kg(-1) of miglitol and nicorandil (46+/-2%). Combination of nicorandil and submaximal dose of miglitol markedly reduced the myocardial infarct size more than miglitol or nicorandil alone. This effect was suggested to be related to the opening of mitochondrial K(ATP) channels.
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PMID:Combination of miglitol, an anti-diabetic drug, and nicorandil markedly reduces myocardial infarct size through opening the mitochondrial K(ATP) channels in rabbits. 1148 14

The gene previously designated as putative cyclodextrinase from Thermotoga maritima (TMG) was cloned and overexpressed in Escherichia coli. The recombinant TMG was partially purified and its enzymatic characteristics on various substrates were examined. The enzyme hydrolyzes various maltodextrins including maltotriose to maltoheptaose and cyclomaltodextrins (CDs) to mainly glucose and maltose. Although TMG could not degrade pullulan, it rapidly hydrolyzes acarbose, a strong amylase and glucosidase inhibitor, to acarviosine and glucose. Also, TMG initially hydrolyzes p-nitrophenyl-alpha-pentaoside to give maltopentaose and p-nitrophenol, implying that the enzyme specifically cleaves a glucose unit from the reducing end of maltooligosaccharides unlike to other glucosidases. Since its enzymatic activity is negligible if alpha-methylglucoside is present in the reducing end, the type of the residue at the reducing end of the substrate is important for the TMG activity. These results support the fact that TMG is a novel exo-acting glucosidase possessing the characteristics of both CD-/pullulan hydrolyzing enzyme and alpha-glucosidase.
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PMID:A novel amylolytic enzyme from Thermotoga maritima, resembling cyclodextrinase and alpha-glucosidase, that liberates glucose from the reducing end of the substrates. 1212 67

New alpha-glucosidase inhibitors, CKD-711 and CKD-711a were produced from the fermentation broth of Streptomyces sp. CK-4416 which was isolated from a forest soil of Jeju Island, South Korea. CKD-711 and CKD-711a were purified by Dowex 50W-2X and Sephadex G-10 column chromatography. In in vitro studies, CKD-711 showed a potent inhibitory activity against a-glucosidase from mammalian, but less inhibition against a-amylase from microorganism and mammalian. CKD-711a showed a lower inhibitory activity than CKD-711.
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PMID:Novel alpha-glucosidase inhibitors, CKD-711 and CKD-711a produced by Streptomyces sp. CK-4416. I. Taxonomy, fermentation and isolation. 1213 13

Pea chloroplastic [alpha]-glucosidase (EC 3.2.1.20) involved in transitory starch degradation was purified to apparent homogeneity by ion exchange, reactive dye, hydroxylapatite, hydrophobic interaction, and gel filtration column chromatography. The native molecular mass and the subunit molecular mass were about 49.1 and 24.4 kD, respectively, suggesting that the enzyme is a homodimer. The enzyme had a Km of 7.18 mM for maltose. The enzyme's maximal activity at pH 7.0 and stability at pH 6.5 are compatible with the diurnal oscillations of the chloroplastic stromal pH and transitory starch accumulation. This pH modulation of the [alpha]-glucosidase's activity and stability is the only mechanism known to regulate starch degradative enzymes in leaves. Although the enzyme was specific for the [alpha]-D-glucose in the nonreducing end as the glycon, the aglycon moieties could be composed of a variety of groups. However, the hydrolysis rate was greatly influenced by the aglycon residues. Also, the enzyme could hydrolyze glucans in which carbon 1 of the glycon was linked to different carbon positions of the penultimate glucose residue. The ability of the [alpha]-glucosidase to hydrolyze [alpha]-1,2- and [alpha]-1,3-glucosidic bonds may be vital if these bonds exist in starch granules because they would be barriers to other starch degradative enzymes. This purified pea chloroplastic [alpha]-glucosidase was demonstrated to initiate attacks on native transitory chloroplastic starch granules.
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PMID:The Role of Pea Chloroplast [alpha]-Glucosidase in Transitory Starch Degradation. 1222 65

An adequate carbohydrate supply contributes to the survival of seeds under conditions of limited oxygen availability. The amount of soluble, readily fermentable carbohydrates in dry cereal seeds is usually very limited, with starch representing the main storage compound. Starch breakdown during the germination of cereal seeds is the result of the action of hydrolytic enzymes and only through the concerted action of [alpha]-amylase (EC 3.2.1.1), [beta]-amylase (EC 3.2.1.2), debranching enzyme (EC 3.2.1.41), and [alpha]-glucosidase (EC 3.2.1.20) can starch be hydrolyzed completely. We present here data concerning the complete set of starch-degrading enzymes in three cereals, rice (Oryza sativa L.), which is tolerant to anaerobiosis, and wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), which are unable to germinate under anoxia. Among the cereal seeds tested under anoxia, only rice is able to degrade nonboiled, soluble starch, reflecting the ability to degrade the starch granules in vivo. This is explained by the presence of the complete set of enzymes needed to degrade starch completely either as the result of de novo synthesis ([alpha]-amylase, [beta]-amylase) or activation of preexisting, inactive forms of the enzyme (debranching enzyme, [alpha]-glucosidase). These enzymes are either absent or inactive in wheat and barley seeds kept under anaerobic conditions.
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PMID:Amylolytic Activities in Cereal Seeds under Aerobic and Anaerobic Conditions. 1222 53

The exponential expansion of the publicly available human DNA sequence database has increasingly facilitated cloning by homology of genes for biochemically defined, functionally similar proteins. We hypothesized that an as-yet uncloned human alpha-glucosidase (human neutral alpha-glucosidase C or GANC) is a previously uncharacterized member of a paralogous human glycosyl hydrolase gene family 31, sharing sequence homology and related, but not identical, functions with other cloned human alpha-glucosidases. We now report both the in silico and physical cloning of two alleles of human neutral alpha-glucosidase (designated GANC on the human gene map). This cloning and correct identification and annotation as GANC was successful only because of the application of the biochemical and genetic information we had previously developed regarding this gene to the results of the in silico method. Of note, this glucosidase, a member of family 31 glycosyl hydrolases, has multiple alleles, including a "null" allele and is potentially significant because it is involved in glycogen metabolism and localizes to a chromosomal region (15q15) reported to confer susceptibility to diabetes.
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PMID:Computer assisted cloning of human neutral alpha-glucosidase C (GANC): a new paralog in the glycosyl hydrolase gene family 31. 1237 Apr 36

Dextran glucosidases show high sequence identity (50%) to Bacillus sp. SAM1606 alpha-glucosidase, which is more specific for short-chain substrates. Sequence comparison of these enzymes as well as molecular modeling studies predicted that the extension of loop 4 of the (beta/alpha)(8)-barrel fold may be responsible for the narrower specificity of SAM1606 alpha-glucosidase with respect to substrate chain length. Indeed, deletion mutants of SAM1606 alpha-glucosidase that lack this extension showed higher relative activities toward dextran and long-chain isomaltooligosaccharides. Kinetic and thermodynamic analyses of oligosaccharide hydrolysis catalyzed by SAM1606 alpha-glucosidase and its deletion mutants suggested that the loss of such extension(s) in loop 4 should energetically destabilize the Michaelis complexes with long-chain substrates to result in smaller differences between the activation free energies for the enzymatic hydrolyses of isomaltoheptaose and isomaltose than those observed for the wild-type enzyme. This is the reason that dextran glucosidase, whose loop 4 is shorter in length, shows broader substrate chain-length specificity than does SAM1606 alpha-glucosidase.
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PMID:Altering the substrate chain-length specificity of an alpha-glucosidase. 1272 8


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