Which hemoglobin may be differentiated from other hemoglobins on the basis of its resistance to denature in alkaline solution?

Which hemoglobin may be differentiated from other hemoglobins on the basis of its resistance to denature in alkaline solution?

• A. A1
• B. A2
• C. C
• D. F

Answer: (D)

The key idea is that different hemoglobins have varying stability when exposed to alkaline (high pH) conditions. Fetal hemoglobin (Hb F) has a unique composition (two alpha and two gamma chains) that makes it more stable in alkaline solution, so it resists denaturation longer than the other common hemoglobins. This property is exploited by the alkali denaturation test to distinguish Hb F from Hb A and Hb A2, which denature more readily under the same conditions. In practice, Hb F remains largely intact while the others denature, allowing its identification and estimation.

The key idea is that different hemoglobins have varying stability when exposed to alkaline (high pH) conditions. Fetal hemoglobin (Hb F) has a unique composition (two alpha and two gamma chains) that makes it more stable in alkaline solution, so it resists denaturation longer than the other common hemoglobins. This property is exploited by the alkali denaturation test to distinguish Hb F from Hb A and Hb A2, which denature more readily under the same conditions. In practice, Hb F remains largely intact while the others denature, allowing its identification and estimation.