One of the most important proteins in the human body is MYOGLOBIN. Today we are discussing Myoglobin in this post.
It found in muscle tissue, where it binds oxygen, helping to provide extra oxygen to release energy to power muscular contractions.
Let us come to the history of Myoglobin. It was the first protein they determined whose structure.
In 1958, Max Perutz and John Kendrew determined the 3D structure of myoglobin by X-ray crystallography.
In 1962 a share of the Nobel Prize for Chemistry was awarded to John C. Kendrew for work, using the technique of X-ray diffraction, that permitted the construction of a three-dimensional model of crystalline sperm-whale myoglobin.
Structure of Myoglobin
How is the structure of myoglobin related to its function? Here is the basic information about myoglobin. It is low molecular weight oxygen binding heme protein. These protein is mainly found in heart and skeletal muscle cells, which occurs in the highest concentration in the striated muscles of vertebrates
- Myoglobin (myoG-Muscle; globinG=a type of protein) is a relatively small, oxygen-binding heme protein, found in muscle cells.
- It is a monomeric protein that has 153 amino acid residues.
- It comprises eight α-helix connected through the turns with an Oxygen binding site.
- Out of 153 amino acids, 121 (79%) are present on the helical regions and it distributes the remaining 32 amino acids over the non-helical areas.
- It has a globular structure.
- The molecular weight of Myoglobin is 16,700, which is a compact macromolecule with oblate, spheroid shaped macromolecule.
- The overall molecular dimensions are 45 X 35 X 25 Ao.
- It contains a heme (prosthetic) responsible for its main function (carrying of oxygen molecules to muscle tissues) and Globin protein.
- It is a protein found in muscles that bind oxygen with its heme ring like hemoglobin.
- Heme group comprises a protoporphyrin organic component and an iron atom in its center.
- It gives muscle and blood their distinctive red color.
- The Myoglobin, a protein that stores oxygen
- Oxidation of the iron atom (Fe2+ -> Fe3+) is mainly responsible for the color of muscle and blood.
- The prosthetic heme group binds to the proximal histidine group while a distal histidine group interacts on the other side of the plane in the structure.
- Myoglobin without its heme prosthetic is designated apo-myoglobin. The main function of apo-myoglobin is to provide a hydrophobic environment for the heme group.
- Myoglobin found in skeletal muscle serves to transport oxygen from the cell membrane to the mitochondria.
Functions of myoglobin
- Myoglobin is found in the muscle cells of animals. It is a protein.
- It acts as an oxygen reservoir (or) Oxygen storage unit it supplies oxygen to working muscles.
- Diving mammals such as seals and whales are able to remain submerged for long periods because they have greater amounts of myoglobin in their muscles than other animals do.
- What Is Special About this protein? It allows the body to have own blood supply like hemoglobin.
- How does myoglobin damage the kidney? When muscle tissue is damaged, very large concentrations of myoglobin enters the kidneys. When this happens, myoglobin is then considered highly toxic and may contribute to acute renal failure.
- Muscle injury is commonly associated with the release of myoglobin and is known to be the cause of heart attacks and many other myoalgia.
- Studies have shown that acute myocardial infarction can be detected with the help of the monitoring of creatine kinase and troponin by electrocardiogram.
Frequently Asked Question (FAQs)
What is the role of myoglobin?
The role of Myoglobin is Oxygen Storage. It facilitates respiration in rapidly respiring muscular tissues. The the solubilityof oxygen increases. It facilitates diffusion of oxygen.
What is the normal range for myoglobin?
The normal range of myoglobin is less than 90mcg/L.
What is the difference between myoglobin and hemoglobin?
Myoglobin is monomeric protein and it is present in Muscular cells. Hemoglobin is a tetrameric protein, which is present in blood. The function of myoglobin is to store oxygen in Myocytes. Hemoglobin functions as gaseous exchanger.