The T form (tense or taut form) of deoxyhemoglobin differs from oxyhemoglobin (the R form or relaxed form) by all EXCEPT:
A) covalent linkages between subunits.
B) specific intrachain hydrogen bonds.
C) between β-subunit salt links (ion-pair bonds).
D) between α-subunits salt links (ion-pair bonds).
E) intrachain salt bridges.

Question

Quizplus · Accepted Answer

Covalent linkages between subunits are present in both deoxyhemoglobin and oxyhemoglobin, so this difference does not differentiate between the two forms. The other choices are all features that distinguish the T form of deoxyhemoglobin from the R form of oxyhemoglobin, as they play a role in stabilizing the different quaternary structures of the two forms. Specifically, hydrogen bonding and salt bridges (ionic interactions) between subunits are key contributors to stabilizing the R (relaxed) form of oxyhemoglobin. In contrast, the T (tense) form of deoxyhemoglobin has fewer such intrachain interactions, leading to a more compact, less stable quaternary structure.

The T Form (Tense or Taut Form) of Deoxyhemoglobin Differs