Mukoproteines

Mukoproteines are a class of proteins that aggregate to form the gel-like matrix of mucosal secretions in animals. The term combines “muko” from mucin with the suffix “-protein,” indicating that these proteins are structurally distinct from typical soluble proteins but are intimately involved in the production and maintenance of mucus.

The primary function of mukoproteines is to provide viscoelastic properties to mucus, enabling it to trap pathogens, particulates, and debris while permitting the passage of nutrients and water. They achieve this by forming extensive intermolecular networks through disulfide bonds, glycosidic linkages, and non-covalent interactions. In humans, secretory mucins—such as MUC5B and MUC5AC—are the most well‑studied examples of mukoproteins; they are heavily O‑glycosylated, allowing them to bind water and expand into mucus strands.

Structurally, mukoproteins share a common high‑molecular‑weight, repetitive amino‑acid sequence that is rich in proline, threonine, and serine residues, which serve as attachment points for carbohydrate chains. This glycosylation pattern confers resistance to proteolytic enzymes and contributes to their large, hydrated state. Beyond the respiratory, gastrointestinal, and genitourinary tracts where mucus is abundant, mukoproteins also play roles in the surface lubrication of arthropods and in the protection of plant pollen pollen exine layers.

Clinical relevance of mukoproteins is evident in diseases where mucus composition or viscosity is altered. Cystic fibrosis and chronic obstructive pulmonary disease feature dehydrated, hyper‑viscous mucus, largely due to changes in the structure or concentration of secretory mucins. In contrast, sputum in cystic fibrosis contains increased concentrations of fragmented mucin fragments, contributing to obstruction of the airways. Recent therapeutic research focuses on mucolytics that target the cross‑linking of mukoproteins, thereby reducing viscosity and improving clearance.