Half-sites oxidation of bovine liver uridine diphosphate glucose dehydrogenase.
6,6-Dithiodinicotinate shows half-of-the-sites reactivity towards the six catalytic-site thiol groups of bovine liver UDP-glucose dehydrogenase. The reagent introduces three intrasubunit disulphide linkages between catalytic-site thiol groups and non-catalytic-site thiol groups and abrogates 60% of the catalytic activity of the hexameric enzyme; excess 2-mercaptoethanol rapidly restores full catalytic activity. These results show the half-of-the-sites behaviour of the enzyme with the reagent and the presence of a non-catalytic-site thiol group capable of forming a disulphide linkage with a catalytic-site thiol group on the same subunit without irreversible denaturation.
D001665:Binding Sites; D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D009539:Nicotinic Acids / Q000378:metabolism*; D010084:Oxidation-Reduction; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000378:metabolism*
D009539:Nicotinic Acids; D002237:Carbohydrate Dehydrogenases; D014533:Uridine Diphosphate Glucose Dehydrogenase