Which of the following enzyme is affected in cyanide poisoning?

Cyanide inhibits the action of cytochrome oxidase and carbonic anhydrase. It blocks the final step of oxidative phosphorylation and prevents the formation of ATP and its use as energy source. Cyanide acts by reducing the oxygen carrying capacity of blood, and by combining with the ferric iron atom of intracellular cytochrome oxidase, preventing the uptake of oxygen for cellular respiration. Ref: The Essentials of Forensic Medicine and Toxicology by KS Narayan Reddy, 27th edition, Page 558-559.