Disulfide bonds in mucus glycoproteins

Disulfide bonds in mucus glycoproteins, specifically mucins, are the primary covalent cross-links responsible for the polymerization of mucin monomers into expansive gel-forming networks (StatPearls, 2023). These bonds are formed between cysteine residues in the amino- and carboxy-terminal domains of mucin proteins, such as MUC5AC and MUC5B, and their density directly determines the viscoelasticity and rheological properties of the mucus layer (Thorax, 2013). In chronic respiratory diseases like cystic fibrosis and COPD, excessive disulfide cross-linking leads to hyper-viscous mucus that obstructs the airways and impairs mucociliary clearance (Journal of Clinical Medicine, 2019). Pharmacological intervention typically involves thiol-based mucolytic agents like N-acetylcysteine, which possess free sulfhydryl groups that interact with the target through a thiol-disulfide exchange reaction (PubChem, 2024). This chemical reduction results in the depolymerization of the mucin network, significantly lowering mucus viscosity and facilitating expectoration. Beyond the lungs, targeting these bonds is also relevant in treating ocular conditions where abnormal mucus consistency causes irritation.

Other names

Mucin disulfide bridgesCystine linkages in mucinsIntermolecular disulfide bonds in mucinsThiol-disulfide exchange target

Reduction of disulfide bonds via thiol-disulfide exchange, leading to the depolymerization of mucin networks and reduction of mucus viscosity.