title: Chemical rescue of alpha3-galactosyltransferase. Implications in the mechanism of retaining glycosyltransferases.
abstract: The mechanism of retaining glycosyltransferases is still poorly understood and the subject of current debate. Both double displacement and front side single displacement (SNi) mechanisms have been proposed. A "chemical rescue methodology" is here applied to a retaining alpha3-galactosyltransferase. Azide as exogenous nucleophile rescues the activity of the inactive E317A mutant to give beta-d-galactosylazide. This result fits best with a double displacement mechanism in which Glu317 is the enzyme nucleophile involved in the formation of a glycosyl-enzyme intermediate.
authors.affiliation: Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Monegal
authors.forename: Antoni
authors.initials: A
authors.lastname: Planas
mesh_terms: D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D015394:Molecular Structure; D009154:Mutation / Q000235:genetics
chemical_list: D016695:Glycosyltransferases