(C) SIRT5 knockdown increases G6PD glutarylation and IDH2 succinylation, respectively, and decreases both enzyme activity. Flag-G6PD or Flag-IDH2 was ectopically expressed in the indicated stable HEK293T cells. G6PD/IDH2 proteins were purified by immunoprecipitated with Flag beads and eluted with Flag peptide, followed by determination of their lysine modifications and enzyme activity. The results are average ± SD of 3 independent experiments **p<0.01, ***p<0.001 (two-tailed unpaired t-test). 