Cdc27 (Cell division cycle protein 27 homolog) is a component of the Anaphase Promoting Comple, Xenopus/Amphibian, (APC). APC is composed of eight protein subunits and is highly conserved in eucaryotic cells. The APC catalyzes the formation of the cyclin B ubiquitin conjugate that is responsible for the ubiquitin mediated proteolysis of B type cyclins. This protein and 3 other members of the APC comple, Xenopus/Amphibian, contain the TPR (tetratricopeptide repeat), a protein domain important for protein protein interaction. This protein was shown to interact with mitotic checkpoint proteins including Mad2,Porcine55CDC and BUBR1, thus may be involved in controlling the timing of mitosis.