Question

Which element is required for synthesis of Vitamin B12?

• A. Iron
• B. Cobalt
• C. Nickel
• D. Magnesium

Hint:

Trace Minerals in Vitamins & Enzymes:
Vitamin $\text{B}_{12}$ $\rightarrow$ COBALT (Cobalamin).
Chlorophyll $\rightarrow$ Magnesium.
Hemoglobin Lactoperoxidase $\rightarrow$ Iron.
Carbonic Anhydrase $\rightarrow$ Zinc.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Micronutrient biochemistry of corrinoid vitamins: Vitamin B12 (cyanocobalamin) contains a central coordinate cobalt ion ($ ext{Co}^{3+}$) chelated inside a planar corrin ring.
Key Formula or Approach:
\[ \text{Vitamin } \text{B}_{12} \text{ Structure: Corrin Ring Macrocycle} + \mathbf{Central \text{ } Cobalt \text{ } Ion (\text{Co}^{3+})} \implies \mathbf{Cobalamin} \]

Step 2: Detailed Explanation:
In biochemistry and dairy nutritional science:
- Vitamin B12 (Cobalamin) is a unique organometallic water-soluble vitamin required for DNA synthesis, methionine regeneration, and propionate metabolism:
- The central coordination core of the corrin ring macrocycle is held by a single atom of the trace element Cobalt (Co) (B).
- Ruminant dairy cattle and ruminal microorganisms obligately require dietary Cobalt to synthesize Vitamin $\text{B}_{12}$ in the rumen, which is subsequently secreted in abundance into bovine milk ($3 - 5\;\mu\text{g/L}$).

Step 3: Final Answer:
Hence, the element required is Cobalt, corresponding to option (B).