Polysulfide stabilization by tyrosine and hydroxyphenyl-containing derivatives that is important for a reactive sulfur metabolomics analysis

Abstract

The physiological importance of reactive sulfur species (RSS) such as cysteine hydropersulfide (CysSSH) has been increasingly recognized in recent years. We have established a reactive sulfur metabolomics analysis by using RSS metabolic profiling, which revealed appreciable amounts of RSS generated endogenously and ubiquitously in both prokaryotic and eukaryotic organisms. The chemical nature of these polysulfides is not fully understood, however, because of their reactive or complicated redox-active properties. In our study here, we determined that tyrosine and a hydroxyphenyl-containing derivative, β-(4-hydroxyphenyl)ethyl iodoacetamide (HPE-IAM), had potent stabilizing effects on diverse polysulfide residues formed in CysSSH-related low-molecular-weight species, e.g., glutathione polysulfides (oxidized glutathione trisulfide and oxidized glutathione tetrasulfide). The protective effect against degradation was likely caused by the inhibitory activity of hydroxyphenyl residues of tyrosine and HPE-IAM against alkaline hydrolysis of polysulfides. This hydrolysis occurred via heterolytic scission triggered by the hydroxyl anion acting on polysulfides that are cleaved into thiolates and sulfenic acids, with the hydrolysis being enhanced by alkylating reagents (e.g. IAM) and dimedone. Moreover, tyrosine prevented electrophilic degradation occurring in alkaline pH. The polysulfide stabilization induced by tyrosine or the hydroxyphenyl moiety of HPE-IAM will greatly improve our understanding of the chemical properties of polysulfides and may benefit the sulfur metabolomics analysis if it can be applied successfully to any kind of biological samples, including clinical specimens.

Control of protein function through oxidation and reduction of persulfidated states

“…Normally, large concentrations of fast-reacting alkylating agents must be used to outcompete cell lysis–induced artifactual oxidation of this extremely reactive thiol ( 35 ). However, because under these conditions protein Cys per- and polysulfides are destroyed via alkylating agent–induced polysulfur chain cleavage ( 30 , 36 ), we here used mild alkylating conditions to capture the perthio- derivatives. Even milder electrophiles such as iodoacetamide have the potential to disrupt polysulfide chains on longer time scales ( 30 ).…”

Differences among patients with and without nonalcoholic fatty liver disease having elevated alanine aminotransferase levels at various stages of metabolic syndrome

“…They occur in diverse polysulfide forms with unique redox-active or reactive chemical properties [ 54 – 56 ]. Sulfur metabolomics was developed to investigate the sulfur metabolic pathways associated with RSS [ 52 , 53 , 57 ]. Although there was no sulfur metabolite that showed statistically significantly different levels between subjects with and without NAFLD having elevation of ALT in our study, the additional results showed that there was a tendency of difference in levels of S-sulfocysteine between subjects having NAFLD with normal ALT levels and those having NAFLD with elevation of ALT levels ( p = 0.072, S1 Table ).…”

H2S and reactive sulfur signaling at the host-bacterial pathogen interface

“…MBB has an intermediate impact resulting in slightly lower yields of per-and polysulfide species relative to HPE-IAM but exhibited significantly better quantitation than N-ethylmaleimide. As a result, many groups now use HPE-IAM for quantification of RSS (175)(176)(177).…”