Understanding Oxyhemoglobin: The Oxygen-Carrying Form of Hemoglobin

Oxyhemoglobin is the normal oxygen-carrying form of hemoglobin in which iron is in the reduced ferrous state. It plays a crucial role in the transport of oxygen from the lungs to various tissues throughout the body. In contrast, methemoglobin, a nonfunctional form of hemoglobin, cannot effectively bind and transport oxygen due to the oxidation of iron from ferric to ferrous.

The Formation and Function of Oxyhemoglobin

Oxyhemoglobin is the haemoglobin bound to oxygen. It is formed in the lungs when oxygen binds to haemoglobin present in red blood cells (RBCs). This binding is reversible, meaning that oxygen can be released in tissues where it is needed. The process of oxygen binding to haemoglobin occurs in a stepwise, cooperative manner, and is essential for maintaining the body's oxygen supply.

The Importance of Haemoglobin in the Respiratory System

Haemoglobin, the respiratory pigment found in red blood cells, is responsible for the transport of oxygen from the lungs to various tissues. Each molecule of haemoglobin can bind four oxygen molecules, and the resulting oxyhemoglobin forms as oxygen is carried to individual cells in the body tissue. Oxygen dissociates in tissues when needed, making oxyhemoglobin a vital component in the body's oxygen transport mechanism.

The Discovery of the Molecular Mass of Hemoglobin

In 1825, J.F. Engelhard discovered that the ratio of iron to protein is identical in the hemoglobins of several species. By using the known atomic mass of iron, he calculated the molecular mass of hemoglobin to be n × 16000, where n is the number of iron atoms per hemoglobin, now known to be 4. This was the first determination of a protein's molecular mass, marking a significant advancement in biochemistry.

Conclusion

Oxyhemoglobin is a key factor in the efficient transport of oxygen within the body. Understanding its formation, function, and the role of haemoglobin in the respiratory system provides valuable insights into the body's mechanisms for maintaining oxygen levels. The discovery of the molecular mass of hemoglobin by Engelhard in 1825 was a pivotal moment in the study of biological molecules and laid the groundwork for future research in this field.