A: Inhibitory activity of selected compounds in an endpoint biochemical assay. Compounds were incubated with SUMO1, E1, E2 enzymes, a fluorescent substrate, and ATP in an appropriate buffer and quenched with EDTA after 90 min. Conversion was quantified by ratiometric peak height in a microfluidic electrophoretic mobility shift assay using a Perkin Elmer EZ Reader II. Values represent the mean of three replicates. B: Evaluation of selected compounds in kinetic biochemical sumoylation assays. Compounds were incubated with SUMO1, E1, E2 enzymes, a fluorescent substrate, and ATP in an appropriate buffer and monitored over the course of 110 minutes. Conversion was quantified by ratiometric peak height in a microfluidic electrophoretic mobility shift assay using a Perkin Elmer EZ Reader II.