Choose the correct statements for oxymyoglobin and cytochrome P₄₅₀ (resting state) from the following: A… · ABC26IN0049
Subject: Inorganic Chemistry · Chapter: Bioinorganic Chemistry · Topic: Metal Toxicity Medicine · Exam: CSIR-NET 2019 · Marks: 2 · Difficulty: Medium
Choose the correct statements for oxymyoglobin and cytochrome $\mathrm{P_{450}}$ (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
(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
Answer: A, C and D — code (2).
Explanation
A — true: both contain the dianion of protoporphyrin-IX (heme b). B — false: in oxymyoglobin the fifth (proximal) ligand is a histidine imidazole N, whereas in cytochrome P450 it is a cysteinate S. C — true: each has a single heme-iron active site. D — true: resting P450 is Fe(III), and oxymyoglobin is described as Fe(III)–O₂⁻ (bound superoxide). Correct set: A, C and D — option (b).