GRXS17 may contribute to the functioning of the purine salvage pathway. A, GRXS17 directly interacts with XDH1. The PJ69-4A yeast strain was cotransformed with GRXS17 in pGBKT7gate and XDH1 in pGADT7gate. The 10× and 100× dilutions of transformed yeasts were dropped on selective medium lacking His. The empty pGADT7gate vector was used as control. One representative from three independent drops is shown. B, XDH1 activity measurements. One hundred micrograms of total protein extract obtained from the indicated plant lines was loaded in each lane (three biological repeats) of a native PAGE and subsequently stained using hypoxanthine as a substrate. C, Purine salvage pathway. Enzymes copurified with GRXS17 in the TAP analysis are encircled. Numbers are averaged relative abundances from five independent samples (grxs17-1/Col-0) of uric acid precursors and ureides mapped on the purine salvage pathway (*P < 0.05; **P < 0.01, Student’s t test; colors: red, decreased; green, increased). The experiments were repeated twice with similar results. WT, Wild type.