title: Beta-glucosidase from Trichoderma reesei. Substrate-binding region and mode of action on [1-3H]cello-oligosaccharides.
abstract: To determine the mode of action of the beta-glucosidase from Trichoderma reesei a method was developed for synthesizing [1-3H]cello-oligosaccharides with specific radioactivities of approximately 3000 Ci/mol. The beta-glucosidase removed glucosyl residues from the non-reducing end of the [1-3H]cello-oligosaccharides in a multiple attack mode with little tendency to attack the substrates repetitively. Values of Km were lower for longer cello-oligosaccharides, whereas values of V remained essentially constant. A subsite map, constructed using values of V/Km for the cello-oligosaccharides, showed that the substrate-binding region comprises primarily three subsites.
mesh_terms: D001665:Binding Sites; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005959:Glucosidases / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D003904:Mitosporic Fungi / Q000201:enzymology*; D009844:Oligosaccharides / Q000138:chemical synthesis / Q000378:metabolism*; D014242:Trichoderma / Q000201:enzymology*; D014316:Tritium; D001617:beta-Glucosidase / Q000378:metabolism*
chemical_list: D002250:Carbon Radioisotopes; D009844:Oligosaccharides; D014316:Tritium; D005959:Glucosidases; D001617:beta-Glucosidase