Zyklon B - Mechanism

Mechanism

Zyklon B is a cyanide-based poisonous gas that interferes with cellular respiration. Specifically, cyanide prevents the cell from producing ATP by binding to one of the proteins involved in the electron transport chain. This protein, cytochrome c oxidase, contains several subunits and has ligands containing iron groups. At one of these iron groups, heme a3, the cyanide component of Zyklon B can bind, forming a more stabilized compound through metal-to-ligand pi bonding. As a result of this new iron-cyanide complex, the electrons which would situate themselves on the heme a3 group can no longer do so. Instead, because of the new bond formed between the iron and the cyanide, these electrons would actually destabilize the compound (based on molecular orbital theory); thus, the heme group will no longer accept them. Consequently, electron transport is halted, and the cell can no longer produce the energy needed to synthesize ATP.