Figure 9.

Evaluation of GS nitration in roots and root nodules treated with nitrate. A, Total soluble proteins were extracted from roots and from 21-d-old root nodules collected from plants treated for 2 d with NH₄NO₃. GS activity was measured by the transferase reaction. B, The cytosolic GS (GS1) immunoreactive bands were quantified by densitometry and the values were plotted. A representative GS western blot of total soluble proteins (10 μg per lane) is shown. C, GS nitration was quantified by sandwich ELISA relative to GS1 polypeptide content. Values shown are means of three biological replicates ± sd, assayed in duplicate.