Mucoprotein


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mucoprotein

[¦myü·kō′prō‚tēn]
(biochemistry)
Any of a group of glycoproteins containing a sugar, usually chondroitinsulfuric or mucoitinsulfuric acid, combined with amino acids or polypeptides.

Mucoprotein

 

a complex biopolymer consisting of protein and carbohydrate components bonded covalently. Mucoproteins are widely distributed in nature. They are components of such secretions in animals and man as saliva, gastric juice, and cerebrospinal fluid, as well as of blood plasma, erythrocytes, urine, chicken egg albumin, the eggs of amphibians and invertebrates, and the cell wall of microorganisms. A number of enzymes and hormones are classified as mucoproteins.

Mucoproteins differ in protein content and in the structure and size of the carbohydrate fraction. They usually contain up to 85 percent protein. Blood elements, however, are the exception, containing up to 80 percent carbohydrates. The carbohydrate fraction of mucoproteins includes the following monosaccharides: N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, D-mannose, fucose, N-acetyl(glycolyl)neuraminic acid, and D-galactose. The peptide chains contain the common amino acids. The biosynthesis of the peptide chains takes place in the ribosomes, while the synthesis of the carbohydrate chains occurs in the Golgi complex with the help of specific enzymes —glycosyltransferases.

The biological functions of mucoproteins are highly varied. They determine the immune properties of the body, the blood-group affiliation, and the elasticity and permeability of tissues. They also participate in intercellular interactions. These functions are primarily determined by the structure of the carbohydrate chains of the mucoproteins. The term “glycoprotein” is more frequently used than “mucoprotein.”

REFERENCES

Derevitskaia, V. A. “Khimiia glikoproteinov.” Uspekhi biologicheskoi khimii, 1967, vol. 8.
Khimiia uglevodov. Moscow, 1967.
Glikoproteiny, vols. 1–2. Moscow, 1969. (Translated from English.)

N. D. GABRIELIAN

References in periodicals archive ?
The intestinal epithelial cells and mucoprotein enhanced EAAL flow in animals (Moncada et al., 2003).
recommend D2-40, a transmembrane mucoprotein, which is expressed by lymphatic endothelial cells.
The walls of the cysts are composed of markedly inflamed fibrous tissue, with evidence of foreign-body- type giant cell reaction, in which mucoprotein material is engulfed, and of myofibroblastic proliferation.
These cells are believed to secrete the proteins or mucoprotein related to the digestion of food.
Until now, it has been maintained that UCC mils have the physicochemical properties of mucus, including viscoelasticity, structure, and mucoprotein content (Bang and Bang, 1978).
Complexes of condensed tannins of sainfoin (Onobrychis-Viciifolia Scop) with fraction 1 leaf protein and with submaxillary mucoprotein, and their reversal by polyethylene glycol and pH.
Complexes of the condensed tannins of sanfoin (Onobrychis viciifolia) with fraction leaf protein and with submaxillary mucoprotein and their reversal by polyethylene glycol and pH.
Complexes of the condensed tannins of sainfoin (Onobrychis viciifolia Scop.) with fraction 1 leaf protein and with submaxillary mucoprotein, and their reversal by polyethylene glycol and pH.
During the 400 million years of evolution, scorpion has developed a complex mixture of mucoproteins, various biochemically active water soluble enzymes, enzyme inhibitors, amines, histamine, lipids, glucose-aminoglycanes, small peptides and various salts in their venom (Zlotkin et al., 1978; Gwee et al., 2002; Nisani et al., 2007; Adiguzel, 2010; Gomes et al., 2010).
We earlier reported PGE having significant GU protective and healing activities through an increase in gastric juice mucoproteins and mucosal glycoproteins and decrease in oxidative stress-induced mucosal damage.
Mesoglycan belongs to a broad class of compounds called glycosaminoglycans that are amino hexose polysaccharides contained in mucoproteins, glycoproteins, and blood group substances.
The samples were stained using staining procedures specific for the desired attributes, as follows: Toluidin Blue (Feder and O'Brien, 1968) for the structural analysis; Coomassie Blue (Wetzel et al., 1989) for total protein content; and Periodic Acid Schiff (PAS, Gahan, 1984) for polyssacharides, acidic carbohydrates and neutral mucoproteins. Thereafter, the slides were mounted in DePex medium (Sigma-Aldrich, United Kingdom).