Abstract
To elucidate the physiological functions of glutathione in plants, we tried to identify glutathionylated proteins in the suspension-cultured Arabidopsis cell [PCP 44: 655]. One of the proteins proved chloroplastic fructose 1, 6-bisphosphate aldolase (FBA), which had four cysteine residues. To examine the target cysteine residue of glutathionylation and its relation to FBA activity, we generated four recombinant mutant FBAs in which one of the four cysteine residues was replaced with alanine. GSH inhibited the activities of wild-type and three mutant FBAs, but had no influence on that of the remaining mutant FBA. This indicates that FBA activity was regulated by the binding of GSH to the specific cysteine residue. On the other hand, GSSG did not inhibit the activities of wild-type and four mutant FBAs, implying that the GSH-dependent regulation of FBA activity is not a simple redox regulation of the cysteine residue. Further analysis is now in progress.
