The changes (from A-D given below) which occur when $\mathrm{O}_{2}$ binds to hemerythrin are
\[ \begin{array}{l} \text{(A) One iron atoms is oxidized} \\ \text{(B) Both the iron atoms are oxidized} \\ \text{(C) } \mathrm{O_2} \text{ binds to one iron atom and is also hydrogen bonded.} \\ \text{(D) } \mathrm{O_2} \text{ binds to both the iron atoms and is also hydrogen bonded.} \end{array} \]
(a)B and C
(b)B and D
(c)A and D
(d)A and C
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
O₂ binding converts the Fe(II)Fe(II) site to Fe(III)Fe(III), so both irons are oxidised. Hydroperoxide binds terminally to one Fe and hydrogen-bonds to the μ-oxo bridge. B and C (a).