Question

Explain the mechanism by which protons exert their effects on hemoglobin.

Answer 1

Haemoglobin's oxygen binding affinity is inversely related to the acidity . Now, through the the biochemical reactions necessary for cellular respiration , increases in the metabolic activity within tissues result in the production of CO2 as a metabolic waste product . the increasein tissue PCO2 leads to an increase in hydrogen ion (H+) concentration , represented as a decrease in pH as the environment undergoes the process of acidosis. These effects decreases haemoglobins's affinity for oxygen , weakening it's binding capacity and the increasing likelihood of dissociation ; this is represented as a rightward shift of the haemoglobin dissociation curve, as haemoglobin unloads oxygen from its binding sites at higher partial pressures of oxygen. Specifically,  it is the association of protons(H+) with the amino acids in haemoglobin that cause conformational change in protein folding, ultimatedly reducing the affinity of binding sites for oxygen molecules. This configuration shift of haemoglobin under the influence of protons is classified as the T form.

haemoglobin exist in two form " T and R " form . This structural change to the T form leads to low affinity haemoglobin whereas the relaxed form leads to a high affinity form of haemoglobin.

At cellular level, through the enzyme carbonic anhydrase , the CO2 and H2O released as by products from cellular respiration are onverted into carbonic acid(H2CO3). IN the pursuit of achieving biochemical equilibrium , carbonic acid partially and reversibly dissociates into H+ ions and its conjucate base , bicarbonate (HCO3). This release of hydrogen ions increases the available concentration of H+ ions within the blood , effectively decreasing the the pH of the environment. To limit the decrease in pH of the environment surrounding peripheral tissues , haemoglobin serves as a buffering agent by releasing its oxygen molecule in favour of binding H+ ion.

Answer 2

In blood after inhalation of oxygen into the body bind with haemoglobin to form oxy haemoglobin during this phenomenon their is no releasing of proton.but when CO2 is released haemoglobin release bhorproton to maintan the equillibrium in between HCO3- ion and CI in red blood cells.so by releasing of bhor protons ŕeleasing of CO2 is takes place.