APC5 (anaphase-promoting complex subunit 5) is a member of the E3 enzyme family. This protein has a molecular weight of approximately 79 kD. The APC5 protein is located in the nucleus during interphase and at the centrosome during metaphase/anaphase. This protein functions with other members of the APC complex as a multisubunit cell cycle ubiquitin ligase, and a regulator of sister chromatid separation by degrading securins. In addition, this protein functions in ubiquitin-dependent cyclin catabolism, metaphase/anaphase transition, and spindle elongation. The APC5 protein comprises one subunit of the anaphase promoting complex including APC1-8, and other probable complex proteins APC9-11, Cdc26, Mnd2, Swm1. The APC complex is inactivated by protein kinase A and is activated by CDC20 and Cdh1. The Poly6111 antibody has been shown to be useful for Western blotting of the human and mouse APC5 protein.