An earlier assay of the coupled activities of SmTGR and peroxiredoxin-2 [ 13 ] was adapted to study the activity of SmTGR alone, using the following principle: SmTGR converts NADPH and GSSG to NADP + and reduced glutathione (GSH), and GSH production can be detected with ThioGlo®, a maleimide derivative of the naphthopyranone fluorophore which fluoresces upon reacting with free thiol groups such as those present in GSH.
Source: wiktionary