A drop in pH would make protonation more likely, and a protonated proximal histidine would not be able to donate its electron density to the iron atom.
<h3>
What is the role of proximal histidine in hemoglobin?</h3>
The first histidine that is bonded to Fe(2+) we call proximal, and the histidine that bonds last, to the oxygen, we call distal.
Histidine is an amino acid most people get from food. It's used in growth, repair of damaged tissues, and making blood cells.
It helps protect nerve cells. It's used by the body to make histamine.
In hemoglobin, the role of proximal histidine is to hold the heme group in the correct location on the hemoglobin chain.
The proximal histidine also pulls the iron in heme out of the plane of the heme molecule. This iron will be pulled back into the plane when it is oxygenated.
The proximal histidine strengthens the iron-imidazole bond and helps to stabilize the oxidoreductase in its higher oxidation (i.e. compounds I and II) states.
To learn more about histidine, refer
brainly.com/question/14115232
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