myoglobin


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myoglobin

(mī'əglō`bĭn), proteinprotein,
any of the group of highly complex organic compounds found in all living cells and comprising the most abundant class of all biological molecules. Protein comprises approximately 50% of cellular dry weight.
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 molecule isolated from the cells of vertebrate skeletal muscle that is both a structural and functional relative of hemoglobinhemoglobin
, respiratory protein found in the red blood cells (erythrocytes) of all vertebrates and some invertebrates. A hemoglobin molecule is composed of a protein group, known as globin, and four heme groups, each associated with an iron atom.
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, the oxygen-transport protein of the blood of higher animals. Myoglobin, which is composed of a single polypeptide chain of 153 amino acidamino acid
, any one of a class of simple organic compounds containing carbon, hydrogen, oxygen, nitrogen, and in certain cases sulfur. These compounds are the building blocks of proteins.
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 residues, has the ability to store oxygen by binding it to an iron atom; iron is part of myoglobin's essential chemical composition. The complete amino acid sequence of myoglobin has been determined; it is a relatively small protein with a molecular weight of approximately 17,000 grams per mole. The distribution of myoglobin among the higher animals is a reflection of its physiological function. It is found abundantly in the tissues of diving mammals, e.g., the whale, the seal, and the dolphin. High concentrations of myoglobin in these animals presumably allows them to store sufficient oxygen to remain underwater for long periods. Myoglobin is found abundantly in man only in cardiac muscle, which, by virtue of its essential function, must possess the capacity for continued activity when environmental oxygen concentrations are low. Myoglobin has been investigated intensely and is the first protein molecule to have been completely described in terms of its three-dimensional geometry. This achievement won the British scientist John Kendrew a share in the 1962 Nobel Prize for Chemistry.

Myoglobin

 

a globular protein that stores molecular oxygen in muscles and delivers it to the oxidative cell systems.

Myoglobin is the first protein whose structure was elucidated by X-ray diffraction analysis (J. Kendrew and his associates, 1957–60). It consists of a single polypeptide chain (about 70 percent of the 153 amino-acid residues are included in the spiral parts). As in hemoglobin, the active center of the myoglobin molecule that binds O2 is heme. The molecular weight of myoglobin is 17,000. The spatial structure of myoglobin resembles the beta chain of hemoglobin. Myoglobin combines reversibly with oxygen even at low partial pressures of oxygen. This is of great physiological importance: the partial pressure of oxygen decreases sharply during muscle contraction as a result of compression of the capillaries, and it is at this very moment that the oxygen needed by the working muscle is released from myoglobin.

The muscles of vertebrates contain about two percent myoglobin per dry tissue mass; the muscles of marine animals capable of staying under water a long time (seal, whale, dolphin) contain about 20 percent. Myoglobin determines the color of muscles in vertebrates.

REFERENCES

Verbolovich, P. A. Mioglobin i ego rol’ v fiziologii i patologii zhivotnykh i cheloveka. Moscow, 1961.
Kendrew, J. C. “Mioglobin i struktura belkov.” Biofizika, 1963, vol. 8, no. 3.

V. O. SHPIKITER

myoglobin

[¦mī·ə¦glō·bən]
(biochemistry)
A hemoglobinlike iron-containing protein pigment occurring in muscle fibers. Also known as muscle hemoglobin; myohemoglobin.
References in periodicals archive ?
Myoglobin Structure and Function: A Multiweek Biochemistry Laboratory.
Muscle cell leakage of myoglobin after long-term exercise and relation to the individual performances.
Preparation of Imprinted Microspheres for Myoglobin. Suspension polymerization was used for the preparation of the myoglobin imprinted microspheres (MIPs).
The results are presented as milligrams of total myoglobin per gram of meat, calculated from the millimolar extinction coefficient of myoglobin at 576 nm.
Myoglobin, a key pathogenic factor in rhabdomyolysis-induced AKI, leads to the development and progression of AKI via different mechanisms.[sup][15] It is acknowledged that inflammation plays a major role in rhabdomyolysis-induced AKI.
Instead, this GPxl polymorphism seems to play a minor role in muscle damage given that although water polo players having the CT heterozygous genotype showed the highest levels of LDH, CK, and myoglobin after exercise, these differences were not statistically significant in comparison with wild-type subjects.
Iron release from the RBC lysate, metHb, or myoglobin was measured utilizing a ferrozine assay [14].
Perhaps our most interesting results concern cyclist number 6 (Table 1): this cyclist showed high values of CK and the highest levels of hsTnT and myoglobin. As myoglobinemia can be indicative of renal impairment (Neumayr et al., 2005) and as cTnT is degraded and then eliminated via the kidneys, this points to a particularly strong impact of exercise on renal function in this individual.
This basic TnT fragments have been suggested as a potential biomarker in beef aging (Muroya et al., 2007) and also a thermostable biomarker in other species (Chen et al., 2002; Ballin et al., 2009).There were differences in spots intensities of protein numbered 5, 6, and 7 among the treatments that corresponded to myoglobin protein.
Venous blood samples for creatinine phosphokinase, lactate dehydrogenase and myoglobin plasma concentrations were obtained at 0, 30 minutes, 6 hours and 24 hours after succinylcholine administration.