(F-G) K413 in IDH2 may be a key succinylation site that is directly targeted by SIRT5. The indicated Flag-tagged IDH2 proteins were overexpressed in HEK293T cells with stable SIRT5 knockdown or SIRT5 co-overexpression. Wild-type and mutant IDH2 proteins were purified by Flag beads and eluted with Flag peptide, followed by measurement of IDH2 enzyme activity. The results are average ± SD of 3 independent experiments *p<0.05, n.s.: not significant (two-tailed unpaired t-test). 