The Protein Man's Blog | A Discussion of Protein Research

4-Vinylpyridine as a derivatizing agent for free thiols and its application in Glutathione assay

Glutathione assay involves quantification of reduced Glutathione (GSH) and Oxidized Glutathione (GSSG) in various organisms or in various tissues, blood samples, plasma, serum or cultured cells. Free thiols such as GSH can be detected by their property of relatively high reactivity compared to other biological molecules. On contrary disulfides such as GSSG does not have any unique property that could be exploited for its quantification. Hence Glutathione disulfide (GSSG) quantification can be done after reducing it to its corresponding thiol (GSH). Thus the most widely adopted methodology for quantification of GSH and GSSG is determination of total GSH concentration, followed by alkylation to remove GSH and then reduction of GSSG and its quantification. GSH concentration in sample can be determined by subtracting glutathione disulfide concentration from total glutathione concentration.  

Monitor oxidative stress to determine the extent of cell damage using a colorimetric gluthathione assay.

Loading controls serve as a vital method of verifying the results acquired through western blotting. Loading controls are antibodies that are used to detect proteins within samples. When western blots are used to determine the levels of protein expression in a sample, loading controls ensure that the results aren't due to loading or protein transfer errors. When using a loading control, the right type of control must first be identified. 

A high background is one of the most common quality control issues encountered during the process of western blotting. When a high background occurs, it can be very difficult to distinguish the relevant data from the irrelevant data. A uniform high background can be caused by numerous issues and may take some work to resolve -- but without resolving the situation, the blot may not be readable.