Hemoglobin is a protein that helps in transfer of oxygen from lungs to different tissues. Hence it is the iron containing pigment of the red blood cell.
Hemoglobin can be divided into different groups and are named differently. This includes:
1. Hemoglobin A: This is the type of hemoglobin that is most common in adults. It is made up of tetramer of goblin chain that has alpha and beta. It is also called HbA. Two chains of the tetra are alpha chains and the other two are the beta chain. Both these chains share common secondary and tertiary structure, with 8 helical segments. This goblin chain has one heme molecule that has porphyrin ring and this porphyrin has 4 pyrole with iron at the centre. When this hemoglobin molecule comes in contact with the oxygen, the iron present binds to oxygen tightly and when two heme molecules comes in contact with each other having oxygen, at that time iron atom gets oxidize. This oxidization of iron atom creates irreversible binding to the oxygen. But since this binding is not necessary, hence this irreversible binding is prevented by goblin by binding of protein around the heme molecule. Therefore, the loose binding of iron with the oxygen helps in release of oxygen in the tissues. Therefore this way, this hemoglobin helps in release of oxygen in the tissues.
2. HemoglobinA2: This hemoglobin is found in adult in 2-3% that is formed by pairing of 2 alpha and two delta chains. It is generally found in very low level in adult human. But in the patient that have beta Thalassemia or in those who are heterozygotes for the same, HbA2 can be seen in increased amount than normal.
3. Hemoglobin F: It is also called fetal hemoglobin that has 2 alpha and 2 gamma structure. This hemoglobin is usually found in very less amount in the adults nearly around 2.5%. Fetal hemoglobin is different from that of adult, because this hemoglobin has higher capacity and more affinity to keep oxygen bind to it. Since oxygen need to cross the placental fluid and reach the fetus, therefore other types of hemoglobin is generally used up by the mother at that time period. So, it is hemoglobin F that keeps oxygen bound to it till it reaches the fetus. This fetal hemoglobin develops after the second month of development and remains till sixth of the month. After sixth month, the level of this hemoglobin slowly gets reduce and hence adult hemoglobin comes in play. But before this fetal hemoglobin, embryonic hemoglobin is present that is made of 2 epsilon and 2 gamma structures. The level can be increase in those having beta thalassemia or sickle cell anemia.
4. Hemoglobin H: This is the other type of hemoglobin that is made of four beta chain. The production of this hemoglobin is done at the time when there is shortage of alpha chain and hence is generally seen in those patient who suffers from alpha thalassemia. These are some of the types of hemoglobin that are produced in the normal way and do not affect the body or the system. But on the other hand there are other types of hemoglobin a well that somehow changes the normal pattern and results in several kinds of diseases. Some of these include:
1. Hb C: this is also an abnormal type of hemoglobin where glutamic acid is substituted in place of lysine residue at 6th position of beta goblin chain.
2. Hb S: these are due to the disorder in the blood that has low oxygen carrying capacity which results in sickle cell anemia.
3. Hb E: it is also an abnormal variant of hemoglobin where mutation has occurred at a single point.
These are some of the abnormal variant of hemoglobin that may put the life of individual in risk. But on the other hand, normal hemoglobin is very much important for individual’s life since it helps in delivery of oxygen. Without this life is almost impossible because oxygen being an important content and if it fails to reach the parts of the body, it can even result in death. Therefore, maintaining hemoglobin level to normal is very important for healthy life.