Hemoglobin

Hemoglobin

Whole blood contains the formed element of red blood cellsThe basic structural and functional units of life. and hemoglobinThe oxygen-carrying protein in red blood cells that gives blood its red color. is contained within those red blood cells.  Hemoglobin as its name indicates is a globular protein instead of a fibrous protein like keratinA strong, fibrous protein that forms the structure of skin, hair, and nails. or collagenA structural protein in the dermis that provides strength and elasticity.. Thinking back to protein structure there were 4 levels of protein structure. When a protein is first made from the DNA recipe, it is just a series of amino acids. These amino acids are bonded together in a chain. That amino acidThe building blocks of proteins, consisting of an amino group, carboxyl group, and side chain. chain then becomes folded into either an alpha helixA common spiral structure in proteins, stabilized by hydrogen bonds. or a beta pleated sheetA protein structure where strands of polypeptides fold into a pleated arrangement.. The helix or sheet then become grouped together to make the tertiary level of protein structure. Tertiary structures then combine to form the final quaternary structure. You see this structure in the call out from that one red blood cell.

We can measure how much hemoglobin is in your red blood cells and report that on a CBC.  The mean corpuscular hemoglobin or M-C-H is the average amount of hemoglobin in your erythrocytes(RBCs): Red blood cells responsible for oxygen transport..  Anemia such as iron deficient anemiaA condition characterized by a deficiency of red blood cells or hemoglobin, leading to reduced oxyge will have a low MCH.

Hemoglobin Components

Hemoglobin actually contains 2 amino acids chains one referred to as alpha and the other referred to as beta. These amino acidA substance that releases hydrogen ions (H⁺) in solution. chains alpha and beta are tertiary structures. The pictures you see here are abbreviations of the tertiary structure. These structures are made-up of many alpha helices and many beta pleated sheets. When 2 alpha chains and two beta chains come together we start to form the final shape of hemoglobin.

Bonded within the alpha and beta chains is a pigment called hemeThe iron-containing portion of hemoglobin that binds oxygen., which has a gray or silvery coloring. This pigment contains another pigment called bilirubinA yellow pigment produced from the breakdown of hemoglobin, excess amounts cause jaundice.. Bilirubin is the same yellowish pigment that gives stomach bileA digestive fluid produced by the liver and stored in the gallbladder; it helps emulsify fats for di its characteristic yellow color. At the center of all this machinery are iron atomsThe smallest units of matter that retain the properties of an element. that are the components capable of binding to oxygen. There are four heme pigments in every hemoglobin molecule. When oxygen attaches to the iron in the heme pigment the pigment changes to a darker color. This is the exact same phenomenon that happens when metal is exposed to oxygen and rusts.

Oxygen Carrying Capacity

There are 4 iron atoms or hema pigments in one hemoglobin molecule. But in one little tiny erythrocyte there are somewhere around 250 million hemoglobin proteinsLarge molecules made of amino acids with various functions in the body.. You can do all kinds of complicated math. What this really means is that there is 1 billion iron atoms in one erythrocyte. This means that one red blood cell can bind to 1 billion oxygen moleculesGroups of atoms bonded together.. Each oxygen molecule will eventually be used to make 36 ATPThe energy currency of cells used for muscle contraction. molecules. That’s a lot of molecules.

Deoxy and Oxyhemoglobin

These are two great words that we should constantly use in this class. We refer to whole blood or erythrocytes and their state concerning oxygen. Deoxyhemoglobin is 1 hemoglobin protein that does not have oxygen bound to the heme pigments. In this case, the heme pigments are very dark in color. They give the red blood cells a very dark brick red color. Because of the reflection of melaninA brown-black pigment made by melanocytes in the stratum basal and given to keratinocytes as melanos in skinThe body’s largest organ, providing protection and regulation., this dark brick red color in your veinsBlood vessels that return deoxygenated blood to the heart (except pulmonary veins, which carry oxyge leads to either cyanosisA bluish skin discoloration due to inadequate oxygen in the blood.. It can also lead to pallorAn unusual paleness of the skin due to reduced blood flow.An unusual paleness of the skin due to red. Cyanosis causes a blue tint or hue to the skin. Pallor is the skin condition that causes a white hue to the skin. Both of these conditions are associated with someone who has low oxygen intake or carrying ability.

Deoxyhemoglobin is found in the erythrocytes in all of your veins of the systemic circuitThe part of the circulatory system that carries oxygenated blood from the heart to the body and retu. It is also in all of your arteriesBlood vessels that carry oxygenated blood away from the heart (except pulmonary arteries, which carr of the pulmonary circuitThe circulation of blood between the heart and the lungs, where blood is oxygenated.. These are the common places where deoxygenated blood exists.  When I was in a foreign country, I used a bathroom in a train station, and never will again.  But, when I closed the door, a black light came on.  I was like, “Is this a joke?”  I mentioned that strangeness to someone I was with. They said that veins are harder to see in a black light.  This was to make it harder to do intravenous drugs in the train station bathroom.  Smart.

Oxyhemoglobin is simply the opposite of deoxyhemoglobinHemoglobin that has released its oxygen and is carrying carbon dioxide or hydrogen ions.. This would be a hemoglobin protein where all four iron atoms are bound to molecular oxygen. In this case the plug takes on a Ruby red or very red color. Oxyhemoglobin is found in the arteries of your systemic circuit and in the veins of your pulmonary circuit. If the blood vessels in your skin close to the surface dilate, it results in a skin condition called arrhythmia. This is normally called blushing and can be due to emotions fever heat or variations in hormones.