Chemical unfolding of enolase from Saccharomyces cerevisiae exhibits a three-state model

Abstract

Enolase is a multifunctional protein that participates in glycolysis and gluconeogenesis and can act as a plasminogen receptor on the cell surface of several organisms, among other functions. Despite its participation in a variety of biological and pathophysiological processes, its stability and folding/unfolding reaction have not been fully explored. In this paper we present, the urea and GdnHClinduced denaturation of enolase studied by means of fluorescence and circular dichroism spectroscopies. We found that enolase unfolds through a highly reversible pathway, populating a stable intermediate species in a range of experimental conditions. The refolding reaction also exhibits an intermediate state that might have a slightly more compact conformation compared to the unfolding intermediate. The thermodynamic parameters associated with the unfolding reaction are presented and discussed.