Oxidised form of enzyme catalase (structure A); prepared by the reaction of [Fe(P)]⁺ (P= porphyrin) with H₂O₂… · ABC26IN0037
Subject: Inorganic Chemistry · Chapter: Bioinorganic Chemistry · Topic: Iron Sulfur Proteins · Exam: CSIR-NET 2013 · Marks: 2 · Difficulty: Medium
Oxidised form of enzyme catalase (structure A); prepared by the reaction of $[\mathrm{Fe(P)}]^{+}$ ( $\mathrm{P}=$ porphyrin) with $\mathrm{H_2O_2}$ has green color because 
A(substitutents on ring are removed for clarity)
A(substitutents on ring are removed for clarity)(a)Oxidation state of iron changed from $\mathrm{Fe}^{\text {III }}$ to $\mathrm{Fe}^{\text {IV }}$
(b)Porphyrin ring is oxidized by one electron
(c)$\pi-\pi^{*}$ transition appears in the visible region
(d)$\mathrm{Fe^{IV}}$ is coordinated with anionic tyrosinate ligand in axial position.
Answer
Answer: B ✓ checked by 4AB · confidence medium
The source book printed A; on checking, B is correct — see the explanation.
Book printed (a).
Explanation
Compound I of catalase is an oxoiron(IV) porphyrin π-cation radical; its green colour comes from the one-electron-oxidised porphyrin ring (b).
Study loop for Bioinorganic Chemistry