Figure 2. Post-translational processing of Vasopressin. The primary translation product of the AVP gene is a large vasopressin-neurophysin II precursor containing both N-terminal signal peptide and C-terminal co-peptin domains. This primary product undergoes sequential post-translational processing in as it moves through the magnocellular neurone toward the nerve terminals in the posterior pituitary. VP: vasopressin. NPII: neurophysin II.