Choose the correct statements for oxymyoglobin and cytochrome $\mathrm{P_{450}}$ (resting state) from the following:A. Both contain dianion of protoporphyrin-IXB. They have same fifth-ligand bonded to metal centre from the protein backboneC. They contain single active siteD. They contain metal ion in +3 oxidation state
(a)A, B and C
(b)A, C and D
(c)A, B and D
(d)B and C only
Answer
Answer: B ✓ checked by 4AB · confidence medium
Explanation
Both contain protoporphyrin-IX²⁻ and a single heme site. Iron is formally Fe(III) in both: Fe(III)–O₂⁻ in oxymyoglobin and resting Fe(III) in P450. The fifth ligands differ: His in myoglobin, Cys thiolate in P450. A, C and D (b).