Cell permeable compound capable of slowing anaphase-promoting complex/cyclosome (APC/C)-dependent proteolysis. Inhibitor of the ubiquitin ligase activity of the APC/C by inhibiting substrate binding to Cdc20. Distinct mechanism of action than proTAME. Blocks mitotic exit only modestly when used alone in cultured cells. A strong synergistic effect is observed when Apcin and proTAME are used simultaneously, providing a more robust mitotic arrest. This may be very beneficial when treating cells that do not efficiently convert proTAME to its active parent compound (TAME) or if experiments demand strong APC/C inhibition.