AChE activity self-breathing control mechanisms regulated by H2Sn and GSH: Persulfidation and glutathionylation on sulfhydryl after disulfide bonds cleavage

Hydrogen sulfide (H 2 S), or dihydrogen sulfane (H 2 S n ), acts as a signal molecule through the beneficial mechanism of persulfidation, known as the post-translational transformation of cysteine residues to persulfides. We previously reported that Glutathione (GSH) could regulate enzyme activity through S-desulfurization or glutathionylation of residues to generate protein-SG or protein-SSG, releasing H 2 S. However, little is known about the mechanisms by which H 2 S n and GSH affect the disulfide bonds . In this study, we provide direct evidences that H 2 S n and GSH modify the sulfhydryl group on Cys272, which forms disulfide bonds in acetylcholinesterase (AChE), to generate Cys-SSH and Cys-SSG, respectively. Glutathionylation of disulfide is a two-step reaction based on nucleophilic substitution, in which the first C S bond is broken, then the S S bond is broken to release H 2 S. H 2 S n and GSH controlled self-breathing motion in enzyme catalysis by disconnecting specific disulfide bonds and modifying cysteine residues, thereby regulating AChE activity. Here, we elucidated H 2 S n and GSH mechanisms on disulfide in the AChE system and proposed a self-breathing control theory induced by H 2 S n and GSH. These theoretical findings shed light on the biological functions of H 2 S n and GSH on sulfhydryl and disulfide bonds and enrich the theory of enzyme activity regulation.