| Comments |
Estimates of absolute concentrations of GSH and GSSG are based on only two assumptions: (1) a cytosolic pH between 6.7 and 7.3 and (2) the absence of other catalysts than glutaredoxin 1 and 2. Although no direct evidence has been found for the latter, it seems, however, highly reasonable given the slow equilibration kinetics observed in the glr1 grx1 grx2 triple knockout. It should also be emphasized that the presence of additional redox catalysts would imply an even lower cytosolic GSSG concentration than the one estimated here. If the GSH concentration of this mutant is close to that of the wild type, as supported by whole cell measurements, we find the cytosolic GSSG concentration of the wild type to be surprisingly low, ~4 µM. |