Question

Class of enzymes which use oxygen as a hydrogen acceptor are known as

• A. Dehydrogenases
• B. Oxidases
• C. Cytochromes
• D. icotinamide coenzymes

Answer 1

The Correct Option is B

To understand which class of enzymes uses oxygen as a hydrogen acceptor, we need to discuss the role of different enzyme classes in biological oxidation-reduction reactions.

Oxidases are a class of enzymes that catalyze oxidation-reduction reactions involving oxygen. The key characteristic of oxidases is their ability to transfer electrons, usually in the form of hydrogen atoms, directly to molecular oxygen (O₂), thereby reducing it to either water (H₂O) or hydrogen peroxide (H₂O₂). This mechanism fits the description of using oxygen as a hydrogen acceptor.

Here is how each option aligns or misaligns with the question:

1. Dehydrogenases: These enzymes typically transfer electrons between substrates and cofactors such as NAD⁺ or FAD, but they do not use molecular oxygen as a hydrogen acceptor directly. Thus, this option is incorrect.
2. Oxidases: As explained above, these enzymes use oxygen as a hydrogen acceptor, which directly aligns with the question. Hence, this is the correct answer.
3. Cytochromes: These are electron-carrying proteins found in the electron transport chain. They participate in electron transfer but do not serve as enzymes using oxygen as a hydrogen acceptor on their own.
4. Nicotinamide coenzymes: These refer to cofactors like NAD⁺ and NADP⁺, which participate in redox reactions but do not involve the direct acceptance of hydrogen by oxygen. Thus, this option is also incorrect.

Conclusion: The enzyme class that uses oxygen as a hydrogen acceptor is Oxidases.