Medical Aspects of Chemical Warfare (2008) - The Black Vault

Cyanide PoisoningFig. 11-1. Likely detoxification reactions for cyanide are shown for this hypothetical cell. The enzyme detoxification systemsare as follows:1. Rhodanese: an intramitochondrial liver enzyme that catalyzes the transfer of sulfur from a donor molecule tocyanide to form thiocyanate. Rhodanese is the major pathway for cyanide detoxification.2. Mercaptopyruvate sulfurtransferases: a group of enzymes widely distributed in the body that catalyze the transferof a sulfane sulfur atom from a donor molecule to a thiophilic acceptor substrate for the limitation of cyanide.3. Thiosulfate reductase: enzymes found in the liver, kidney, heart, brain, intestine, and testis that use electrons fromthiols, which in vivo probably use electrons from glutathione, to reduce the sulfane sulfur atoms of inorganicthiosulfate and organic thiosulfonate anions to the sulfide level. Sulfide production from these thiol-dependentreductases is thought to be used in the synthesis of Fe-S proteins.4. Cystathionase: enzymes widely distributed in the body that can transfer sulfur from one cysteine to another,generating thiocysteine and pyruvate. Transamination of cysteine leads to the production of thiosulfate and thelimitation of cyanide.5. Albumin: molecules that act like an enzyme in the detoxification of cyanide. Albumin molecules contain sulfursites that bind to and limit cyanide.ADP: adenosine diphosphateATP: adenosine triphosphateATCA: 2-aminothiazoline-4-carboxylic acidCN − : cyanide ionCNMetHb: cyanomethemoglobinCNO: cyanateDIDS: 4,4’-diisothiocyano-2,2’-disulfonic stilbeneDMAP: dimethylaminophenolDNP: deoxyribonucleoproteinEDERF: endothelium-derived relaxing factorHb: hemoglobinMedHb: methemoglobinPAPP: p-aminopropiophenoneR: reduction factorS: substrateDrawing: Courtesy of Steven I Baskin, PhD, and Fred Sidell, PhD, US Army Research Institute of Chemical Defense, AberdeenProving Ground, Md.375