Glutathione redox potential measured using Grx1-roGFP2

Range -310 to -320 mV
Organism Budding yeast Saccharomyces cerevisiae
Reference Morgan B, Sobotta MC, Dick TP. Measuring E(GSH) and H2O2 with roGFP2-based redox probes. Free Radic Biol Med. 2011 Dec 1 51(11):1943-51. doi: 10.1016/j.freeradbiomed.2011.08.035. p.1944 left column 3rd paragraphPubMed ID21964034
Primary Source [26] Braun, N. A. Morgan, B. Dick, T. P. Schwappach, B. The yeast CLC protein counteracts vesicular acidification during iron starvation. J. Cell Sci. 123: 2342–2350 2010. doi: 10.1242/jcs.068403.PubMed ID20530571
Method P.1944 left column 2nd paragraph: "In this article [investigators] describe methods and considerations for the use of two fluorescence-based, genetically encoded probes that enable real-time, nondisruptive, and subcellular compartment-specific measurement of the redox potential of the GSH:GSSG redox couple (EGSH) and changes in H2O2 concentration. These probes are fusion proteins consisting of redox-active green fluorescent protein 2 (roGFP2) genetically fused to the redox enzymes human glutaredoxin-1 (Grx1), for measurement of EGSH, and Orp1 from Saccharomyces cerevisiae, for measurement of H2O2 as described previously [refs 24,25]."
Comments P.1944 left column 3rd paragraph: "[Investigators’] measurements of the cytosolic EGSH in S. cerevisiae using the Grx1-roGFP2 probe typically give values of between -310 and -320 mV([primary source] and unpublished data),which is consistent with a number of other studies employing genetically encoded fluorescent probes [refs 7,8,27–29]. Assuming a total glutathione concentration of 10 mM this would imply a GSH:GSSG of between 20,000:1 and 40,000:1. Thus, GSSG appears to be present only in nanomolar amounts in the cytosol, suggesting that original estimates of the GSH:GSSG in this compartment are wrong by 2 to 3 orders of magnitude."
Entered by Uri M
ID 111465