Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals.[5][6][7][8][9] Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobin has a higher affinity for oxygen and does not have cooperative binding with oxygen like hemoglobin does.[8][10] Myoglobin consists of non-polar amino acids at the core of the globulin, where the heme group is non-covalently bounded with the surrounding polypeptide of myoglobin. In humans, myoglobin is found in the bloodstream only after muscle injury.[11][12][13]
High concentrations of myoglobin in muscle cells allow organisms to hold their breath for a longer period of time. Diving mammals such as whales and seals have muscles with particularly high abundance of myoglobin.[13] Myoglobin is found in Type I muscle, Type II A, and Type II B; although many older texts describe myoglobin as not found in smooth muscle, this has proved erroneous: there is also myoglobin in smooth muscle cells.[14]
Myoglobin was the first protein to have its three-dimensional structure revealed by X-ray crystallography.[15] This achievement was reported in 1958 by John Kendrew and associates.[16] For this discovery, Kendrew shared the 1962 Nobel Prize in chemistry with Max Perutz.[17][18] Despite being one of the most studied proteins in biology, its physiological function is not yet conclusively established: mice genetically engineered to lack myoglobin can be viable and fertile, but show many cellular and physiological adaptations to overcome the loss. Through observing these changes in myoglobin-depleted mice, it is hypothesised that myoglobin function relates to increased oxygen transport to muscle, and to oxygen storage; as well, it serves as a scavenger of reactive oxygen species.[19]
In humans, myoglobin is encoded by the MB gene.[20]
Myoglobin can take the forms oxymyoglobin (MbO2), carboxymyoglobin (MbCO), and metmyoglobin (met-Mb), analogously to hemoglobin taking the forms oxyhemoglobin (HbO2), carboxyhemoglobin (HbCO), and methemoglobin (met-Hb).[21]
^ abcGRCh38: Ensembl release 89: ENSG00000198125 – Ensembl, May 2017
^ abcGRCm38: Ensembl release 89: ENSMUSG00000018893 – Ensembl, May 2017
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Ordway GA, Garry DJ (Sep 2004). "Myoglobin: an essential hemoprotein in striated muscle". The Journal of Experimental Biology. 207 (Pt 20): 3441–6. doi:10.1242/jeb.01172. PMID 15339940.
^Wick MR, Hornick JL (2011). "Immunohistology of Soft Tissue and Osseous Neoplasms". Diagnostic Immunohistochemistry. Elsevier. pp. 83–136. doi:10.1016/b978-1-4160-5766-6.00008-x. ISBN 978-1-4160-5766-6. Myoglobin is a 17.8-kD protein that is found in cardiac and skeletal muscle and that forms complexes with iron molecules.
^Feher J (2017). "Oxygen and Carbon Dioxide Transport". Quantitative Human Physiology. Elsevier. pp. 656–664. doi:10.1016/b978-0-12-800883-6.00064-1. ISBN 978-0-12-800883-6. Highly oxidative muscle fibers contain a lot of myoglobin. It has two functions in muscle: it stores oxygen for use during heavy exercise, and it enhances diffusion through the cytosol by carrying the oxygen. By binding O2, myoglobin (Mb) provides a second diffusive pathway for O2 through the cell cytosol.
^ abWilson MT, Reeder BJ (2006). "MYOGLOBIN". Encyclopedia of Respiratory Medicine. Elsevier. pp. 73–76. doi:10.1016/b0-12-370879-6/00250-7. ISBN 978-0-12-370879-3. Myoglobin (Mb) is a heme-containing globular protein that is found in abundance in myocyte cells of heart and skeletal muscle.
^Boncyk JC (2007). "Perioperative Hypoxia". Complications in Anesthesia. Elsevier. pp. 193–199. doi:10.1016/b978-1-4160-2215-2.50052-1. ISBN 978-1-4160-2215-2. Myoglobin serves both as an O2 buffer and to store O2 in muscle. All known vertebrate myoglobins and β-hemoglobin subunits are similar in structure, but myoglobin binds O2 more avidly at low Po2 (Fig. 47-5) because it is a monomer (i.e., it does not undergo a significant conformational change with oxygenation). Thus, myoglobin remains fully saturated at O2 tensions between 15 and 30 mm Hg and unloads its O2 to the muscle mitochondria only at very low O2 tensions.
^Hardison RC (Dec 2012). "Evolution of Hemoglobin and Its Genes". Cold Spring Harb Perspect Med. 2 (12): a011627. doi:10.1101/cshperspect.a011627. PMC 3543078. PMID 23209182.
^Chung MJ, Brown DL (July 2018). "Diagnosis of acute myocardial infarction.". In Brown DL (ed.). Cardiac Intensive Care-E-Book. pp. 91–98.e3. doi:10.1016/B978-0-323-52993-8.00009-6. ISBN 9780323529938. S2CID 260507329. Myoglobin is not specific for myocardial necrosis, however, especially in the presence of skeletal muscle injury and renal insufficiency.
^Sekhon N, Peacock WF (2019). "Biomarkers to Assist in the Evaluation of Chest Pain". Biomarkers in Cardiovascular Disease. Elsevier. pp. 115–128. doi:10.1016/b978-0-323-54835-9.00011-9. ISBN 978-0-323-54835-9. S2CID 59548142. myoglobin is not specific for the death of cardiac myocytes, and levels can be elevated in renal disease as well as damage to skeletal muscle.
^ abNelson DL, Cox MM (2000). Lehninger Principles of Biochemistry (3rd ed.). New York: Worth Publishers. p. 206. ISBN 0-7167-6203-X. (Google books link is the 2008 edition)
^Qiu Y, Sutton L, Riggs AF (Sep 1998). "Identification of myoglobin in human smooth muscle". Journal of Biological Chemistry. 273 (36): 23426–32. doi:10.1074/jbc.273.36.23426. PMID 9722578.
^(U.S.) National Science Foundation: Protein Data Bank Chronology (Jan. 21, 2004). Retrieved 3.17.2010
^Kendrew JC, Bodo G, Dintzis HM, Parrish RG, Wyckoff H, Phillips DC (Mar 1958). "A three-dimensional model of the myoglobin molecule obtained by x-ray analysis". Nature. 181 (4610): 662–6. Bibcode:1958Natur.181..662K. doi:10.1038/181662a0. PMID 13517261. S2CID 4162786.
^Stoddart C (1 March 2022). "Structural biology: How proteins got their close-up". Knowable Magazine. doi:10.1146/knowable-022822-1. Retrieved 25 March 2022.
^The Nobel Prize in Chemistry 1962
^Garry DJ, Kanatous SB, Mammen PP (2007). "Molecular Insights into the Functional Role of Myoglobin". Hypoxia and the Circulation. Advances in Experimental Medicine and Biology. Vol. 618. Springer. pp. 181–93. doi:10.1007/978-0-387-75434-5_14. ISBN 978-0-387-75433-8. PMID 18269197.
^Akaboshi E (1985). "Cloning of the human myoglobin gene". Gene. 33 (3): 241–9. doi:10.1016/0378-1119(85)90231-8. PMID 2989088.
^Harvey JW (2008). "Iron Metabolism and Its Disorders". Clinical Biochemistry of Domestic Animals. Elsevier. pp. 259–285. doi:10.1016/b978-0-12-370491-7.00009-x. ISBN 978-0-12-370491-7. Myoglobin is an oxygen-binding protein located primarily in muscles. Myoglobin serves as a local oxygen reservoir that can temporarily provide oxygen when blood oxygen delivery is insufficient during periods of intense muscular activity. Iron within the heme group must be in the Fe+2 state to bind oxygen. If iron is oxidized to the Fe+3 state, metmyoglobin is formed.
Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost...
heartbeat. Some of the muscle breakdown products, such as the protein myoglobin, are harmful to the kidneys and can cause acute kidney injury. The muscle...
Biology in Cambridge. Kendrew determined the structure of the protein myoglobin, which stores oxygen in muscle cells. In 1947 the MRC agreed to make a...
hemoglobin. Myoglobin, the oxygen-binding protein used in muscles, is absent from all icefish skeletal muscles. In 10 species, myoglobin is found in the...
science, red meat is defined as any meat that has more of the protein myoglobin than white meat. White meat is defined as non-dark meat from fish or chicken...
muscle cells use myoglobin to accelerate oxygen diffusion and act as localized oxygen reserves for times of intense respiration. Myoglobin also stores the...
Myoglobinuria is the presence of myoglobin in the urine, which usually results from rhabdomyolysis or muscle injury. Myoglobin is present in muscle cells as...
difference augmented by considerably more oxygen bound to hemoglobin and myoglobin of diving mammals, enabling prolongation of submersion after capillary...
as carbaminohemoglobin. Additionally, many other hemoproteins such as myoglobin, Cytochrome P450, and mitochondrial cytochrome oxidase are affected, along...
Prize in Chemistry with John Kendrew, who sequenced the globular protein myoglobin. The role of hemoglobin in the blood was elucidated by French physiologist...
first protein structures to be solved were hemoglobin by Max Perutz and myoglobin by John Kendrew, in 1958. The use of computers and increasing computing...
which is either hemoglobin or myoglobin. This mechanism of facilitated diffusion of oxygen by hemoglobin or myoglobin was discovered and initiated by...
a liquefied meat product that contains fewer fats, pigments and less myoglobin than unprocessed dark meats. Meat slurry is more malleable than dark meats...
of myoglobin and other juices decreases. The color change is due to changes in the oxidation of the iron atom of the heme group in the myoglobin protein...
similar to hemoglobin or myoglobin but using the metal cobalt instead of iron (hence the name). Just like hemoglobin and myoglobin, the coboglobins are able...
to kidney failure. The renal changes were due to the buildup of excess myoglobin, resulting from the destruction of muscles from lack of oxygen. The progressive...
Metmyoglobin is the oxidized form of the oxygen-carrying hemeprotein myoglobin. Metmyoglobin is the cause of the characteristic brown colouration of meat...
altogether, instead classifying meat by objective characteristics such as myoglobin or heme iron content, lipid profile, fatty acid composition, cholesterol...
is commonly diagnosed using the urine myoglobin test accompanied by high levels of creatine kinase (CK). Myoglobin is the protein released into the bloodstream...
powder). In processed meats, potassium nitrate reacts with hemoglobin and myoglobin generating a red color. Nitre, or potassium nitrate, because of its early...
varying color, which is a reflection of myoglobin content. Type I fibers appear red due to the high levels of myoglobin. Red muscle fibers tend to have more...
tissue is also possible, depending on among other things the content of myoglobin, mitochondria, and myosin ATPase etc.[citation needed] The word muscle...
series of eight alpha helical segments. Two prominent members include myoglobin and hemoglobin. Both of these proteins reversibly bind oxygen via a heme...
(EVERY) Heme proteins such as myoglobin and hemoglobin give meat its characteristic texture, flavor, color, and aroma. The myoglobin and leghemoglobin ingredients...
similar to myoglobin. One leghemoglobin protein consists of a heme bound to an iron, and one polypeptide chain (the globin). Similar to myoglobin and hemoglobin...
recognized metal system in biology. Other oxygen transport systems include myoglobin, hemocyanin, and hemerythrin. Oxidases and oxygenases are metal systems...
and pigs, contain a protein called myoglobin, which binds oxygen and iron atoms. When beef is cooked, the myoglobin proteins undergo oxidation, and gradually...
other globins with a hem group such as myoglobin can also catalyse the same reaction. The presence of myoglobin in urine gives a positive reaction in the...
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