Anaphase accounts for approximately 1% of the cell cycle's duration. It begins with the regulated triggering of the metaphase-to-anaphase transition. Metaphase ends with the destruction of B cyclin. B cyclin is marked with ubiquitin which flags it for destruction by proteasomes, which is required for the function of metaphase cyclin-dependent kinases (M-Cdks). Anaphase starts when the anaphase promoting complex marks an inhibitory chaperone called securin with ubiquitin for destruction. Securin is a protein which inhibits a protease known as separase. Once destroyed, separase is unleashed and breaks down cohesin, a protein responsible for holding sister chromatids together. The centromeres are split, and the new daughter chromosomes are pulled toward the poles. They take on a V-shape as they are pulled back.
While the chromosomes are drawn to each side of the cell, the non-kinetochorespindle fibers push against each other, in a ratcheting action, that stretches the cell into an oval.
Once anaphase is complete, the cell moves into telophase.