Figure 1From: The ultimate radiochemical nightmare: upon radio-iodination of Botulinum neurotoxin A, the introduced iodine atom itself seems to be fatal for the bioactivity of this macromolecule BoNT-A molecule with heavy chain, light chain and disulphide connection. The heavy chain (100 kD) is important for docking and endocytosis of BoNT-A in the nerve end terminal. In the nerve end terminal, the light chain (50 kD) cleaves SNAP-25 protein, which is essential in the fusion of acetylcholine vesicles with the nerve end membrane [17].Back to article page