The amino acid side chain high affinity for Ca2+ and Cu2+ in metallo-proteins is A. carboxylate in both the cases B. imidazole in both the cases C. carboxylate for Ca2+ and imidazole for Cu2+ D. imidazole for Ca2+ and carboxylate for Cu2+

The correct answer is C. carboxylate for Ca2+ and imidazole for Cu2+.

Carboxylate groups are negatively charged, while imidazole groups are neutral. Calcium ions are positively charged, while copper ions are also positively charged. Therefore, carboxylate groups will have a higher affinity for calcium ions, while imidazole groups will have a higher affinity for copper ions.

Carboxylate groups are found in the side chains of aspartic acid and glutamic acid. Imidazole groups are found in the side chain of histidine.

Here is a more detailed explanation of each option:

• Option A: Carboxylate in both the cases. This is not correct because imidazole groups have a higher affinity for copper ions than carboxylate groups.
• Option B: Imidazole in both the cases. This is not correct because carboxylate groups have a higher affinity for calcium ions than imidazole groups.
• Option C: Carboxylate for Ca2+ and imidazole for Cu2+. This is the correct answer because carboxylate groups have a higher affinity for calcium ions, while imidazole groups have a higher affinity for copper ions.
• Option D: Imidazole for Ca2+ and carboxylate for Cu2+. This is not correct because carboxylate groups have a higher affinity for calcium ions than imidazole groups.