title: Stereochemical course of glucan hydrolysis by barley (1-->3)- and (1-->3, 1-->4)-beta-glucanases.
abstract: The stereochemical course of hydrolysis of Laminaria digitata laminarin and barley (1-->3, 1-->4)-beta-glucan by barley (1-->3)-beta-glucanase (E.C. 3.2.1.39) isoenzyme GII and (1-->3, 1-->4)-beta-glucanase (EC 3.2.1.73) isoenzyme EII, respectively, has been determined by 1H-NMR. Both enzymes catalyse hydrolysis with retention of anomeric configuration (e-->e) and may therefore operate via a double displacement mechanism. We predict that all other members of Family 17 of beta-glycosyl hydrolases also follow this stereochemical course of hydrolysis.
mesh_terms: D002236:Carbohydrate Conformation; D002352:Carrier Proteins / Q000378:metabolism; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000378:metabolism*; D005936:Glucans / Q000737:chemistry / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism*; D001467:Hordeum / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D058619:Maltose-Binding Proteins; D008956:Models, Chemical; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D047071:beta-Glucans
chemical_list: D002352:Carrier Proteins; D005936:Glucans; D058619:Maltose-Binding Proteins; D011134:Polysaccharides; D011993:Recombinant Fusion Proteins; D047071:beta-Glucans; C067858:beta-glucan, (1-3)(1-4)-; C008247:laminaran; D006026:Glycoside Hydrolases; D004693:Glucan Endo-1,3-beta-D-Glucosidase; C028020:licheninase