This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory chain, Subject name: Biochemistry
All the following are inhibitors of cytochrome oxidase except 
Select and explain. 
A. Carbon monoxide, B. Amytal, C. Cyanide, D. Azide
B: Amytal
Answer: B: Amytal 
Explanation: Site-III (Complex IV) * Cyanide * 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. Amobarbital (Amytal) and Secobarbital: Inhibits electron transfer through NADH-Q reductase.Ref: MN Chatterjea Textbook of Medical Biochemistry, 8th edition, page no: 143