Consider the following statements for deoxy-hemerythrin and deoxy-hemocyanin:A. they are involved in $\mathrm{O}_2$ transport in biological systemsB. they contain two metal ions in their active siteC. active site metal centres are bridged by amino acid residuesD. they prefer to bind only one $\mathrm{O}_2$ per active siteThe correct statements are
(a)A, B and D
(b)A, C and D
(c)B, C and D
(d)A and C
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
Both transport O₂, both have two metal ions at the active site, and both bind one O₂ per site. Only hemerythrin's irons are bridged by amino-acid carboxylates; the two coppers of hemocyanin have no bridging residue. A, B and D (a).