Question

Which one of the following transition metals is present in Vitamin B₁₂?

• A. Mn
• B. Co
• C. Zn
• D. Cu

Hint:

Remember: The “co” in cobalamin (Vitamin Bsubscript{12}) refers to cobalt — a unique metal found in this essential vitamin.

Answer 1

The Correct Option is B

Step 1: Understand what Vitamin B₁₂ is.
Vitamin B₁₂, also known as cobalamin, is a complex organometallic compound that plays an essential role in red blood cell formation, neurological function, and DNA synthesis.
Step 2: Identify the central metal ion in Vitamin B₁₂.
The name “cobalamin” comes from cobalt (Co), which is the central metal ion in the corrin ring of the Vitamin B₁₂ molecule. The cobalt atom is coordinated at the center of this ring, which is similar in structure to a porphyrin ring but slightly contracted.
Step 3: Eliminate the other options.
Mn (Manganese): Not present in Vitamin B₁₂.
Zn (Zinc): Important in enzymes like carbonic anhydrase, but not in B₁₂.
Cu (Copper): Found in proteins like ceruloplasmin but not in B₁₂.
Step 4: Confirm the correct answer.
Only Cobalt (Co) is associated with Vitamin B₁₂, making option (2) the correct one.