Cytochrome oxidase can be poisoned by all, EXCEPT:: (A) Cyanide, (B) Hydrogen sulphide, (C) Carbon monoxide, (D) Carbon dioxide
Answer is D. Cytochrome oxidase is a haemo-protein widely distributed in many tissues. It is the terminal component of the chain of respiratory carriers found in mitochondria and transfers electrons resulting from the oxidation of substrate molecules by dehydrogenases to their final acceptor, oxygen. The enzyme is poisoned by carbon monoxide, cyanide, and hydrogen sulfide. Ref: Harper 28thedition, chapter 12.