Hemoglobin C disease has altered solubility properties similar to hemoglobin S disease. What accounts for this altered solubility?
A) Heme iron is in the ferric form rather than ferrous form.
B) The hemoglobin remains in the tense structure.
C) A nonpolar amino acid is substituted for a polar amino acid.
D) A polar amino acid is substituted near the pocket where heme binds.

Question

Quizplus · Accepted Answer

In hemoglobin C disease, a glutamic acid residue is replaced by lysine at position 6 of the beta globin chain. This substitution results in the formation of abnormal hemoglobin molecules, known as hemoglobin C, which have altered solubility properties similar to hemoglobin S disease. The substitution of a nonpolar amino acid (lysine) for a polar amino acid (glutamic acid) near the pocket where heme binds reduces the water solubility of hemoglobin, causing the molecules to aggregate and form insoluble fibers.

Hemoglobin C Disease Has Altered Solubility Properties Similar to Hemoglobin