title: A cell-associated oligo-1,6-alpha-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1.
abstract: Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.
authors.affiliation: Department of Biological Sciences, University of Waikato, Hamilton, New Zealand.
authors.forename: A R
authors.initials: AR
authors.lastname: Plant
authors.forename: S
authors.initials: S
authors.lastname: Parratt
authors.forename: R M
authors.initials: RM
authors.lastname: Daniel
authors.forename: H W
authors.initials: HW
authors.lastname: Morgan
mesh_terms: D001421:Bacteria, Anaerobic / Q000201:enzymology*; D002413:Cations, Divalent / Q000494:pharmacology; D004187:Disaccharides / Q000378:metabolism; D005960:Glucosides / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009834:Oligo-1,6-Glucosidase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature; D014312:Trisaccharides / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D004187:Disaccharides; D005960:Glucosides; D014312:Trisaccharides; C025193:4-nitrophenyl beta-D-glucoside; D006026:Glycoside Hydrolases; D009834:Oligo-1,6-Glucosidase