C Securin ubiquitination by APC/C and either UBE2C WT or K157E, resolved by SDS-PAGE and fluorescent scanning. Quantification of 4 or more ubiquitins added on the substrate (right) are calculated as a fraction of total ubiquitination and analyzed by an unpaired Welch's t-test (**** p ≤ 0.0001, n=5 independent, technical replicates). Error bars: SEM. D Similar to C, Ub-securin ubiquitination by APC/C and either UBE2D2 WT or charge-swap variants. Quantification of 4 or more ubiquitins (right) added on the substrate are calculated as a fraction of total ubiquitination and analyzed by one-way ANOVA (**** p ≤ 0.0001, n=4 independent, technical replicates). Error bars: SEM. 