Hemoglobin

Hemoglobin ► Blood can carry very little oxygen in solution. ► Hemoglobin is required to carry oxygen around. ► Hemoglobin is found in red blood cells

Hemoglobin ► In fact if the body had to depend upon dissolved oxygen in the plasma to supply oxygen to the cells – ► The heart would have to pump 140 liters per minute - instead of 4 liters per minute.

Hemoglobin ► Each red blood cell can carry about one million molecules of oxygen in its lifetime ► Hemoglobin is 97% saturated when it leaves the lungs ► Under resting conditions is it about 75% saturated when it returns.

Hemoglobin ► Hemoglobin is made from two similar proteins that "stick together". ► Both proteins must be present for the hemoglobin to pick up and release oxygen normally. ► One of the component proteins is called alpha, the other is beta.

Hemoglobin ► Blood cells are made up of two components. ► The hemoglobin is in solution inside the cell. ► The cell is surrounded by a membrane that holds in the hemoglobin. ► A rough analogy would be a rubber water balloon. ► The rubber would be the membrane, and the water would be the hemoglobin

Porphyrin Ring ► At the core of the molecule is porphyrin ring which holds an iron atom.porphyrin ► An iron containing porphyrin is termed a heme. heme ► This iron atom is the site of oxygen binding. ► The name hemoglobin is the concatenation of heme and globin

Hemoglobin ► Hemoglobin is a remarkable molecular machine that uses motion and small structural changes to regulate its action. ► Oxygen binding at the four heme sites in hemoglobin does not happen simultaneously. ► Once the first heme binds oxygen, it introduces small changes in the structure of the corresponding protein chain.

Hemoglobin ► These changes nudge the neighboring chains into a different shape, making them bind oxygen more easily. ► Thus, it is difficult to add the first oxygen molecule, but binding the second, third and fourth oxygen molecules gets progressively easier and easier. ► This provides a great advantage in hemoglobin function.

Hemoglobin ► When blood is in the lungs, where oxygen is plentiful, oxygen easily binds to the first subunit and then quickly fills up the remaining ones. ► Then, as blood circulates through the body, the oxygen level drops while that of carbon dioxide increases.

Hemoglobin ► In this environment, hemoglobin releases its bound oxygen. As soon as the first oxygen molecule drops off, the protein starts changing its shape. ► This prompts the remaining three oxygens to be quickly released. ► In this way, hemoglobin picks up the largest possible load of oxygen in the lungs, and delivers all of it where and when needed.

Iron and Hemoglobin ► The mineral, iron, plays an important role in the body’s delivery and use of oxygen to and by working muscles. ► The mineral, iron, plays an important role in the body’s delivery and use of oxygen to and by working muscles. ► It binds oxygen to hemoglobin, which then travels in the bloodstream to locations throughout the body.

Iron and Hemoglobin ► Generally, the more oxygen there is being delivered, the greater the body’s ability to perform work. ► For this reason, iron receives much attention for its role in supporting aerobic exercise, and it has been postulated that a lack of iron in the body can reduce aerobic capacity and impair endurance performance.

Iron and Hemoglobin ► Iron deficient red blood cells ► Low number of cells ► Note the hollow and blanched appearance of the red blood cells.

Sickle Cell anemia ► Sickle Cell Anemia is a genetic disorder that is characterized by the formation of hard, sticky, sickle-shaped red blood cells, in contrast to the biconcave-shaped red blood cells (RBCs) found in “normal” individuals. ► This disease is caused by a mutation in hemoglobin.

Thalassemia ► It consists of two different proteins, an alpha and a beta. ► If the body doesn't produce enough of either of these two proteins, the red blood cells do not form properly and cannot carry sufficient oxygen. ► The result is anemia that begins in early childhood and lasts throughout life.

Porphyria ► Porphyria is a group of different disorders caused by abnormalities in the chemical steps leading to the production of heme

Porphyria ► It is characterized by extreme sensitivity to light (exposure to sunlight causes vesicular erythema), reddish-brown urine, reddish-brown teeth, and ulcers which destroy cartilage and bone, causing the deformation of the nose, ears, and fingers. Mental aberrations, such as hysteria, manic-depressive psychosis, and delirium, characterize this condition as well.