Glucose binds to which site on hemoglobin?

• A. N-terminal valines
• B. C-terminal valines
• C. Beta chain arginines
• D. Heme iron

Answer: (A)

Non-enzymatic glycation targets the amino groups on proteins. In hemoglobin, the primary site is the free amino group at the N-terminus of the β-globin chains, which are valine residues. glucose reacts with this N-terminal amino group to form a Schiff base, which rearranges to a more stable Amadori product, yielding HbA1c. This is why HbA1c reflects long-term blood glucose. The heme iron isn’t involved in this covalent reaction, and the other sites mentioned are not the main glycation targets.