Contrary to expectation, reaction with sulfite is not generally correlated with the presence of negatively or positively charged amino acid residues near the disulfide loop but is determined by individual sequence and surface features in every single protein.

coli glutaredoxin being more susceptible molecules. coli thioredoxin being less reactive and plant thioredoxins and E.

Although they are all thought to be highly conserved in three-dimensional structure, their reactivities towards sulfite and the effects of 6 M guanidinium chloride (not affecting, or enhancing sulfitolysis) vary strongly in the series, with E. A comparative study of sulfitolysis in 12 different thioredoxins and glutaredoxins of bacterial and plant origin has been made. Sulfitolysis of Escherichia coli thioredoxin was found to be associated with an increase in fluorescence at 345 nm. In contrast to most other disulfide-containing proteins, this S-S bridge is cleaved by millimolar concentrations of sulfite in the absence of protein denaturing agents at pH 7-8 and ambient temperature however, the reaction is not quantitative. Thioredoxins and glutaredoxins, in their oxidized form, possess a single disulfide bridge located on an edge of the small compact molecules.

Avast filezilla sulfitolysis