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)

Maltose metabolism was investigated in the hyperthermophilic archaeon Thermococcus litoralis. Maltose was degraded by the concerted action of 4-alpha-glucanotransferase and maltodextrin phosphorylase (MalP). The first enzyme produced glucose and a series of maltodextrins that could be acted upon by MalP when the chain length of glucose residues was equal or higher than four, to produce glucose-1-phosphate. Phosphoglucomutase activity was also detected in T. litoralis cell extracts. Glucose derived from the action of 4-alpha-glucanotransferase was subsequently metabolized via an Embden-Meyerhof pathway. The closely related organism Pyrococcus furiosus used a different metabolic strategy in which maltose was cleaved primarily by the action of an alpha-glucosidase, a p-nitrophenyl-alpha-D-glucopyranoside (PNPG)-hydrolyzing enzyme, producing glucose from maltose. A PNPG-hydrolyzing activity was also detected in T. litoralis, but maltose was not a substrate for this enzyme. The two key enzymes in the pathway for maltose catabolism in T. litoralis were purified to homogeneity and characterized; they were constitutively synthesized, although phosphorylase expression was twofold induced by maltodextrins or maltose. The gene encoding MalP was obtained by complementation in Escherichia coli and sequenced (calculated molecular mass, 96,622 Da). The enzyme purified from the organism had a specific activity for maltoheptaose, at the temperature for maximal activity (98 degrees C), of 66 U/mg. A Km of 0.46 mM was determined with heptaose as the substrate at 60 degrees C. The deduced amino acid sequence had a high degree of identity with that of the putative enzyme from the hyperthermophilic archaeon Pyrococcus horikoshii OT3 (66%) and with sequences of the enzymes from the hyperthermophilic bacterium Thermotoga maritima (60%) and Mycobacterium tuberculosis (31%) but not with that of the enzyme from E. coli (13%). The consensus binding site for pyridoxal 5'-phosphate is conserved in the T. litoralis enzyme.
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PMID:Maltose metabolism in the hyperthermophilic archaeon Thermococcus litoralis: purification and characterization of key enzymes. 1034 46

Glycosyl amino esters (2-13) on reaction with different isocyanates resulted in quantitative conversion to glycosyl ureas (14--32). Few of the selected ureas (15-20, 22-28, 30 and 32) on cyclative amidation with DBU/TBAB/4 A MS gave respective dihydropyrimidinones in fair to good yields (33-47). The compounds were screened for alpha-glucosidase inhibitory activity and two (19 and 23) of them showed strong inhibition against rat intestinal alpha-glucosidase. The compounds were also screened against Mycobacterium aurum, however, only one (19) of them exhibited marginal antitubercular activity.
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PMID:Synthesis and bioevaluation of glycosyl ureas as alpha-glucosidase inhibitors and their effect on mycobacterium. 1278 61

An rpoB sequence-based evaluation of 100 Mycobacterium avium complex (MAC) clinical isolates led to the identification of five respiratory tract isolates that were potential representatives of three novel MAC species. Distinctive phenotypic features of isolates 62863 and 5356591(T) included a pseudomycelium morphology and both esterase and acid phosphatase activities. These two isolates exhibited sequence similarities of 99.8 % for the 16S rRNA gene, 86.3 and 86.1 % for 16S-23S rRNA gene internal transcribed spacer (ITS-1) sequence, 96.7 and 97.8 % for rpoB and 97.6 and 97.4 % for hsp65, respectively, with the type strain of Mycobacterium chimaera, the most closely related species. Isolates 3256799 and 5351974(T) lacked alpha-mannosidase and beta-glucosidase activities. They exhibited sequence similarities of 99.6 % for the 16S rRNA gene, 90.1 and 90.4 % for ITS-1, 97.8 % for rpoB and 98.0 and 98.1 % for hsp65, respectively, with the type strain of M. chimaera, the most closely related species. Isolate 4355387(T) lacked urease and alpha-glucosidase activities, but it exhibited valine arylamidase, cystine arylamidase and acid phosphatase activities. It had sequence similarities of 99.3 % for the 16S rRNA gene, 51.8 % for ITS-1, 97.1 % for rpoB and 97.8 % for hsp65 with the type strain of Mycobacterium colombiense, the most closely related species. A phylogenetic tree based on concatenated 16S rRNA gene, ITS-1, rpoB and hsp65 sequences showed the uniqueness of these five isolates as representatives of three novel species, with bootstrap values >/=95 % in all nodes. On the basis of these phenotypic and genetic characteristics, these five isolates are proposed as representatives of three novel MAC species: Mycobacterium marseillense sp. nov., with strain 5356591(T) (=CCUG 56325(T) =CIP 109828(T) =CSUR P30(T)) as the type strain; Mycobacterium timonense sp. nov., with strain 5351974(T) (=CCUG 56329(T) =CIP 109830(T) =CSUR P32(T)) as the type strain; and Mycobacterium bouchedurhonense sp. nov., with strain 4355387(T) (=CCUG 56331(T) =CIP 109827(T) =CSUR P34(T)) as the type strain.
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PMID:Mycobacterium marseillense sp. nov., Mycobacterium timonense sp. nov. and Mycobacterium bouchedurhonense sp. nov., members of the Mycobacterium avium complex. 1962 9