Cyanide is toxic because it: (A) Inhibits cytochrome oxidase, (B) Forms cyan meth Hb, (C) Inhibits ATP carrier in mitochondria, (D) Inhibits Na-K-ATP ase
Answer is A. Site-III (Complex IV) (CYTOCHROME OXIDASE ) * Cyanide Blocks electron transfer from cyt b to c1 Inhibits terminal * H2S * Azide transfer of electrons to molecular O2 * Co (Carbon monoxide): Inhibits Cyt. oxidase by combining with O2 binding site. It can be reversed by illumination with light.Ref: MN Chatterjea Textbook of Medical Biochemistry, 8th Edition