Which of the following enzyme is affected by cyanide poisoning?: (A) G-6-P dehydrogenase deficiency, (B) Isomerase, (C) Cytochrome oxidase, (D) None of the above
Answer is C. Cyanide is a chemical asphyxiant; binding to cellular cytochrome oxidase, it blocks the aerobic utilization of oxygen. Unbound cyanide is detoxified by metabolism to thiocyanate, a much less toxic compound that is excreted in the urine. Ref: Blanc P.D. (2012). Chapter 57. Cyanide. In K.R. Olson (Ed), Poisoning & Drug Overdose, 6e.