Cyanide is toxic because it
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
Inhibits cytochrome oxidase
Forms cyan meth Hb
Inhibits ATP carrier in mitochondria
Inhibits Na-K-ATP ase
Respiratory chain