In vitro neddylation reactions with UBE2M are insensitive to H2O2. Poly-NEDD8 reactions were prepared with NAE, UBE2M, and NEDD8 as in Figure 1E. Before reactions were started, increasing concentrations of H2O2 (as indicated) were added to the NEDD8 reactions. Subsequently the reactions were incubated at 30°C for the indicated amount of time. Reactions were stopped by the addition of LDS sample loading buffer and resolved by SDS-PAGE before processing for Western blot analysis with the indicated antibodies. 