Mucin (Latin: mucus) is a glycoprotein produced by many cells of the body. It is a component of mucus, which lubricates and protects body tissues. Mucin is also present in other body fluids, such as tears and saliva.
Mucins are large, complex molecules that consist of a protein backbone with attached sugar chains (oligosaccharides). The sugars give mucins their characteristic slimy texture. Mucins play an important role in protecting the body from infection and keeping tissues moist. They also help to repair damaged tissue and keep the digestive system functioning properly.
There are two types of mucins: membrane-bound and secreted. Membrane-bound mucins are found on the surface of cells that line the gastrointestinal tract, respiratory tract, and reproductive tract. Secreted mucins are produced by goblet cells, which are specialized cells found in the lining of the gastrointestinal tract.
Mucins were first discovered in 1848 by German anatomist Karl Friedrich Burdach, who described them as “a viscous, sticky substance” that coats epithelial surfaces. In 1884, French physician Louis Pasteur demonstrated that mucus protects against stomach acidity and plays a role in immunity. In the early 20th century, scientists began to study the chemical structure of mucin molecules and their role in disease.
Mucins are important components of normal gut function. They form a barrier between the luminal contents of the intestine and the epithelial cells that line the gut wall. This barrier prevents pathogenic bacteria and toxins from entering circulation and causing infection or inflammation. Mucins also trap small particles of food or bacteria so they can be eliminated from the body before they cause harm. Additionally, mucins lubricate stool so it can move easily through the intestines during elimination..
In some diseases, such as inflammatory bowel disease (IBD), cystic fibrosis, or cancer, there is an overproduction of certain types of mucin or a change in its composition. This can lead to problems with intestinal function or increased susceptibility to infection..