Question

In the lab, it is possible to take hemoglobin and treating it with low concentrations of denaturants, dissociate(break apart) the hemoglobin tetramer (a2b2) into a dimer, without disrupting the conformation of the individual protomers. What is the subunit composition of the dimer? Would the new dimer bind oxygen? If so, would the binding curve be more like native hemoglobin, R-hemoglobin or T-hemoglobin. Explain your answer.

Answer 1

Haemoglobin is made up of Heme pigment which is iron containing and globin is protein part. so, haemoglobin is red colour iron containing pigment present in RBCs that carry oxygen from lungs which brings from outside to the tissue level. And it is a tetrameric protein have 2 alpha and 2 beta chains.

The protein exist as tetramer dimer equilibirium. When the protein get dissociated than it resulting in decreasing the concentration and shift the equilibirium towards the dimeric form.

The hills coeficient for oxygen binding is reduces when the concentration of the haemoglobin is decreases . So, the dimer formed has less oxygen affinity. Since the T - state having lower oxygen affinity and dimer will have the T- haemoglobin state.