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. Band C
(b)A, C and D
(c)A. B and D
(d)Band C only
Answer
Answer (as printed): B
Explanation
Both oxymyoglobin and cytochrome $\mathrm{P_{450}}$ contain dianion of protoporphyrin-IX.Oxymyoglobin has fifth ligand bonded to metal centre from protein backbone but in cytochrome $\mathrm{P_{450}}$ one S-atom of cysteine is coordinated instead of histidine from protein backbone.Both contain single active site $[\mathrm{Fe^{III}}]$