B. Rozell et al., IMMUNOCHEMICAL CHARACTERIZATION AND TISSUE DISTRIBUTION OF GLUTAREDOXIN (THIOLTRANSFERASE) FROM CALF, European journal of cell biology, 62(2), 1993, pp. 314-323
Glutaredoxin catalyzes glutathione-dependent disulfide oxidoreduction
reactions in a coupled system with NADPH, GSH and glutathione reductas
e and has an active site disulfide/dithiol with the sequence -Cys-Pro-
Tyr-Cys-. Calf thymus glutaredoxin (thiol-transferase), which contains
two additional structural half-cystine residues, was purified to homo
geneity, using a modification of the previously described isolation pr
ocedure. This method involved a pI-shift of glutaredoxin, obtained aft
er oxidation of the fully reduced form with hydroxyethyl-disulfide, fo
llowed by CM-Sepharose chromatography. On both SDS- and IEF-gels the p
rotein migrated as one band (M(r) 12000). The pure protein was used to
affinity-purify rabbit antiglutaredoxin antibodies obtained by immuni
zation with the oxidized form of glutaredoxin. Using these antibodies
the distribution of glutaredoxin was mapped in calf organs and tissues
by Western blots and by immunohistochemistry. Glutaredoxin was demons
trated in all organs investigated. Western blots showed the presence o
f weak additional high molecular weight bands of unknown identity in c
ertain organs. The immunohistochemical analyses revealed that glutared
oxin is highly expressed in a wide variety of cell types, both epithel
ial and mesenchymal. The distribution and occurrence in the calf organ
s was similar to that previously described for thioredoxin in the rat.
There were some exceptions: e.g., follicular cells in the ovary did n
ot contain immunohistochemically demonstrable glutaredoxin but express
ed thioredoxin. Particularly striking were observations of strong glut
aredoxin immunoreactivity in oocytes in the ovary and the pattern of g
lutaredoxin in epithelial tissue of the skin and tongue reflecting dif
ferential expression during cell differentiation. The distribution dem
onstrated that glutaredoxin serves functions apart from the originally
described role as hydrogen donor for ribonucleotide reductase which o
nly occurs in replicating cells. Such functions should relate particul
arly to glutathione-catalyzed protein disulfide oxidoreductions and ce
llular signalling by redox regulating mechanisms.