Bohr Effect

Bohr effect

This is the effect seen on hemoglobin. It was first observed by Christian Bohr (Neil Bohr's father). The Bohr effect is the release of hydrogen ions from hemoglobin into the binding of oxygen.

Hemoglobin is present in two states R-state and T-state. R-state has higher affection for O2 than T-state. Each of these conferencing stations has a different set of permanent interactions.

The interactions responsible for the Bohr effect include positively charged acidic groups. In the T-state these groups participate in ion pairs, and thus stabilize in the protonated state (their PKs are raised). In the R-state these interactions are absent and as a result acidic groups release protons. The ratio O 0.6 protons per O2 bound continues.

The importance of the deaf effect

The Bohr effect plays an important role in the transport of oxygen and carbon dioxide. The body uses a bicarbonate buffer system to maintain a stable blood pH, provided by the balance shown below.

CO2 + H2O <---> H2CO3

H2CO3 <---> H + HCO3-

Overall balance:

CO2 + H2O <---> H + HCO3-

Another useful balance is hemoglobin (Hb) and oxygen:

Hb + O2 <---> HbO2 + H +

The conversion of CO2 to bicarbonate is mediated by the enzyme carbonic anhydrase.

The events of the transport system can be divided into two areas; Capillaries and lungs.

Lungs

The partial pressure of O2 is higher in the lungs. It favors binding favors of O2 by Hb, and thus releases protons. This proton release affects the bicarbonate balance, causing it to move in the direction of CO2 formation. It works to drive the CO2 we release.

Capillary

The cells in the capillaries produce CO2 by normal respiration. This shifts the bicarbonate balance towards ionization. This increase in hydrogen ion concentration reverses the Hb balance back towards the release of O2.

Thus we see that carbon dioxide escapes to the lungs and oxygen is extracted to the capillaries where this myoglobin moves to the muscles and other cells.

The Bohr effect is a phenomenon that was first described in 1904 by the Danish physiologist Christian Bohr. Oxygen binding of hemoglobin (Oxygen - see hemoglobin dissociation curve) is inversely related to both acidity and concentration of carbon dioxide.  That is, the Bohr effect refers to a change in the rotation of oxygen dissociation due to a change in the concentration of carbon dioxide or the pH of the atmosphere. Because carbon dioxide reacts with water to form organic acids, increasing CO2 lowers blood pH,  resulting in hemoglobin proteins releasing their oxygen load. In contrast, a decrease in carbon dioxide increases pH, which causes hemoglobin to take in more oxygen.

In the early 1900's, Christian Bohr was a professor at the University of Copenhagen in Denmark, already known for his work in the field of respiratory physiology.  He has studied the solubility of oxygen, carbon dioxide and other gases in various liquids over the past two decades,  and conducted extensive research on hemoglobin and its oxygen. In 1903, he began working closely with karl Hasselbach and his two university colleagues, August Krogh, using whole blood instead of hemoglobin solutions in an attempt to experimentally mimic the work of Gustav von Hufner. Hufner suggested that oxygen-hemoglobin binding is hyperbolic in curve shape, but after extensive experimentation the Copenhagen group determined that this curve was actually sigmoidal. Moreover, in the process of forming innumerable dissociation curves, it became clear quickly that the high partial pressure of carbon dioxide to move the curves to the right.  Further experimentation in differentiating the concentration of CO2 provided quick conclusive evidence, confirming the existence of what will soon be known as the Bohr effect.