Does the Glutathione Assay kit distinguish between oxidized and reduced glutathione?
Yes, the Glutathione Assay kit does measure total glutathione as well as oxidized and reduced glutathione. The addition of 4-vinylpyridine to the standard or cell extract blocks reduced glutathione (GSH) but not oxidized glutathione (GSSG). Thus the only form remaining after 4-vinylpyridine treatment is GSSG. The reduced form (GSH) is calculated by first determining total glutathione with the kit, and then treating with 4-vinylpyridine. Subtracting GSSG from total glutathione then gives the reduced GSH concentration.
