Glutathione serves as the major thiol-redox buffer in the defense against Reactive Oxygen Species (ROS) in eukaryotes. Firmicutes bacteria utilize as thiol redox buffer bacillithiol (Cys-GlcN-Mal, BSH) and Actinomycetes produce the related redox buffer mycothiol (AcCys-GlcN-Ins, MSH). In eukaryotes, proteins are post-translational modified to S-glutathionylated proteins in response to oxidative st ...