Current Methods for the Identification of Sites of S-Glutathionylation and S-Nitrosylation in Proteins

Abstract

Chemical modification of protein thiols has profound effects on the structure and catalytic activity of proteins. These post-translational modifications are often transient in nature, and therefore characterization of them can be elusive, especially in the case of S-nitrosothiols. Many of the methods discussed here involve a trapping mechanism where the modified thiol is selectively reduced and covalently labeled, thus enabling secondary detection or isolation via various techniques. Protocols have also been developed to detect and map sites of S-glutathionylation and are also discussed here. Throughout this review, 'S-modification' will refer to both S-nitrosylation and S-glutathionylation collectively. Herein, we provide a brief review of current methodology available for the empirical elucidation of sites susceptible to S- modification, histochemical visualization of cellular compartments susceptible to S-modification as well as an account of factors currently known to dictate S-modification susceptibility.