title: Significance of the enzymatic properties of yeast S39A enolase to the catalytic mechanism.
abstract: The S39A mutant of yeast enolase (isozyme 1), prepared by site-directed mutagenesis, has a relative Vmax of 0.01% and an activation constant for Mg2+ ca. 10-fold higher, compared with native enzyme. It is correctly folded. There is little effect of solvent viscosity on activity. We think that the loop Ser36-His43 fails to move to the 'closed' position upon catalytic Mg2+ binding, weakening several electrostatic interactions involved in the mechanism.
authors.affiliation: Dept. of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Brewer
authors.forename: C V
authors.initials: CV
authors.lastname: Glover
authors.forename: M J
authors.initials: MJ
authors.lastname: Holland
authors.forename: L
authors.initials: L
authors.lastname: Lebioda
mesh_terms: D009154:Mutation; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D010751:Phosphopyruvate Hydratase