title: Inactivation of alpha-glucosidase by the active-site-directed inhibitor, conduritol B epoxide.
abstract: Conduritol B epoxide is an active-site-directed inhibitor of some glucosidases. The inactivation of alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) from Monascus ruber by conduritol B epoxide is irreversible and first-order with respect to time and inhibitor concentration. The inactivation is prevented by the presence of the substrate maltose. The pH-dependence of Vmax for maltose indicated the participation of two dissociating groups with pK values of 4.1 and 5.8 in the enzyme-substrate complex. Modification of the alpha-glucosidase with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride led to loss of activity, which suggests that a carboxyl group(s) is located at the active site of alpha-glucosidase.
mesh_terms: D001665:Binding Sites; D005959:Glucosidases / Q000037:antagonists & inhibitors*; D065089:Glycoside Hydrolase Inhibitors; D006863:Hydrogen-Ion Concentration; D007294:Inositol / Q000031:analogs & derivatives* / Q000494:pharmacology; D007700:Kinetics; D008320:Maltose
chemical_list: D065089:Glycoside Hydrolase Inhibitors; D007294:Inositol; D008320:Maltose; D005959:Glucosidases; C011423:conduritol epoxide