A mucoprotein is a

glycoprotein Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycos ...

composed primarily of

mucopolysaccharide Glycosaminoglycans (GAGs) or mucopolysaccharides are long, linear polysaccharides consisting of repeating disaccharide units (i.e. two-sugar units). The repeating two-sugar unit consists of a uronic sugar and an amino sugar, except in the case o ...

s. Mucoproteins can be found throughout the body, including the

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...

reproductive organs A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

, airways, and the synovial fluid of the knees. They are called mucoproteins because the carbohydrate quantity is more than 4% unlike glycoproteins where the carbohydrate quantity is less than 4%. Mucoprotein is produced in the cecum of the gastrointestinal tract. During gallbladder cancer, mucoprotein is over expressed. Sustaining a

brain injury An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or o ...

will lead to decreased mucoprotein production. The result is an alteration of

gut microbiota Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut m ...

as seen in mice.

Function

Mucoproteins are the proteins that are the building blocks of

mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...

, which is a protective barrier to the

epithelia Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellula ...

of cells. It is semipermeable, so it acts as a barrier to most bacteria and pathogens, while allowing for the uptake of

nutrients A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

, and

hormones A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and beh ...

Protein Structure

Mucoproteins are composed of o-linked carbohydrates as well as highly glycosylated proteins, which are held together by

disulfide bonds In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

. The viscosity of the mucus depends on the strength of the disulfide bonds. When these disulfide bonds are broken, the viscosity of the mucus secretions is reduced.

Clinical Significance

Mucolytic medications will break through the disulfide bonds and lower the viscosity of the mucus, thus allowing the hypersecreted mucus to be more manageable. A hypersectretion of mucus is often a symptom of

pulmonary diseases Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bron ...

respiratory infections Respiratory tract infections (RTIs) are infectious diseases involving the respiratory tract. An infection of this type usually is further classified as an upper respiratory tract infection (URI or URTI) or a lower respiratory tract infection (LRI ...

. There are two subgroups in mycolytic medications and each one works differently to control the hypersecreted mucus. * Classic mucolytic medications these medications change the disulfide bond by reducing it to a

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

bond, thus thoroughly breaking down the mucoproteins and making the mucus more manageable. * Peptide mucolytic medications these medications depolymerize DNA polymer and F-actin links that are present when the mucus hypersecretes. This preserves the mucins that are helpful to the epithelial tissue of the lungs.

External links

Bibliography

* Houlden, Ashley; Goldrick, Maire C.; Brough, David; Vízi, Elek Sylvester; Lénárt, Nikolett; Martinecz, Bernadett;Roberts, Ian S.D.;Dénes, Ádám(2016)."Brain injury induces specific changes in the caecal microbiota of mice via altered autonomic activity and mucoprotein production". ''Brain, Behavior, and Immunity.'' * Aksoy, Murat; Aydin Faruk; Guven, Suleyman; Kart, Cavit; Tosun, Ilknur (2012). "The effect of ethinyl estradiol and drospirenone-containing oral contraceptives upon mucoprotein content of cervical mucus." ''ScienceDirect''. * Aronson, J. K., ed. (2016-01-01). "Acetylcysteine", Meyer's Side Effects on Drugs (Sixteenth Edition), Oxford: Elsevier, pp 23-25. * Gupta, Rishab; Wadhwa, Roopma (2022). "Mucolytic Medications." ''National Library of Medicine.'' * Cone, Richard A (2009). "Barrier properties of mucus." ''ScienceDirect''. * Kumar, Puneet; Shukla, Priyesh; Kumari, Soni; Dixit, Ruhi; Narayan, Gopeshwar; Dixit, V. K., & Khanna, A. K. (2021). Expression of Mucoproteins in Gallbladder Cancer. ''Indian Journal of Surgery''

References

Glycoproteins {{Protein-stub