From Columbia University and the New York Center for Voice and Swallowing Disorders, New York (Dr Blitzer), and the Department of Head and Neck Surgery, University of California, Los Angeles (Dr Binder). Drs Blitzer and Binder have received consultant fees from Allergan Inc, Irvine, Calif, and Dr Blitzer has received research grants from Allergan Inc.
Clostridium botulinum produces 7 serologically distinct toxins that are designated A, B, C, D, E, and F. They all have similar structure (a dichain with a disulfide bond) and a molecular weight of about 150 d. The light chain is a zinc-dependent metalloprotease, in which the substrate is one of the fusion proteins responsible for docking and ultimately exocytosis of the acetylcholine-containing vesicle. Each serotype light chain cleaves a specific residue of one of these proteins, thus preventing the formation of this docking complex and hence, preventing neurotransmitter exocytosis.1-2
Blitzer A, Binder WJ. Cosmetic Uses of Botulinum Neurotoxin Type AAn Overview. Arch Facial Plast Surg. 2002;4(4):214-220. doi: