Choose the correct statements for oxymyoglobin and cytochrome P₄₅₀ (resting state) from the following:

A. Both contain dianion of protoporphyrin-IX

B. They have same fifth-ligand bonded to metal centre from the protein backbone

C. They contain single active site

D. They contain metal ion in +3 oxidation state

Answer is

Concept:

→ Oxymyoglobin controls oxygen utilization and supply. By acting as a scavenger of the bioactive molecule NO, oxymyoglobin regulates both oxygen supply and utilization.

→ The cytochrome P450 (CYP) enzymes are membrane-bound hemoproteins that play a pivotal role in the detoxification of xenobiotics, cellular metabolism and homeostasis.

Explanation:

→ The dianion of protoporphyrin-IX is a common prosthetic group found in both oxymyoglobin and cytochrome P₄₅₀ (resting state), and it binds to a metal ion in the center of the molecule.

Oxyhaemoglobin

Cytochrome P450

→ This metal ion is usually in the +2 or +3 oxidation state, and in the case of oxymyoglobin and cytochrome P₄₅₀ (resting state), it is in the +2 oxidation state.

→ Both oxymyoglobin and cytochrome P₄₅₀ (resting state) contain a single active site where the substrate binds and undergoes a chemical reaction.

→ In oxymyoglobin, the active site binds oxygen, while in cytochrome P₄₅₀ (resting state), it binds the substrate to be metabolized.

Statement B is incorrect: Both oxymyoglobin and cytochrome P₄₅₀ contain a heme group with a central iron atom, the specific fifth-ligand bonded to the metal center can differ between the two proteins. In oxymyoglobin, the fifth-ligand is a histidine residue from the protein backbone, while in cytochrome P450, it can be a variety of ligands, including thiolate, imidazole, or water molecules.

Conclusion:
The correct answer is  A, C and D .