Quick Biochemistry - Vitamins (Section 2 - No. 41)
In a carboxylation reaction where biotin acts as a coenzyme, a CO₂ molecule is captured. To which part of the biotin molecule is the carboxyl group covalently linked?
A nitrogen atom (N₁) within the biotin structure
A sulfur atom in a thiophene ring
The a-Amino group of lysine
An a-Amino group found in a protein