The physicochemical characterisation of pepsin degraded pig gastric mucin

• Published in: International journal of biological macromolecules Vol. 87; pp. 281 - 286
• Main Authors: Abodinar, Atiga, Tømmeraas, Kristoffer, Ronander, Elena, Smith, Alan M., Morris, Gordon A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2016
• Subjects: Animals; Chemical Phenomena; Compact conformation; Drug Carriers - chemistry; Drug Carriers - metabolism; Gastric Mucins - chemistry; Gastric Mucins - metabolism; Hydrodynamics; Mechanical Phenomena; Pepsin A - metabolism; Pepsin degraded mucin; Physicochemical properties; Proteolysis; Rheology; Swine; Pepsin degraded mucin; Compact conformation; Physicochemical properties
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2016.02.062

•The physicochemical properties of extensively degraded mucin were investigated.•Mucin consisted of fucose, galactose, glucosamine, glucosamine and sialic acid.•Weight average molar mass was 1×106g/mol and intrinsic viscosity was ∼0.4dL/g.•Critical overlap concentration was determined to be 10–11% w/v.•Data is consistent with a weak polyelectrolyte behavior and compact conformation. Mucins are the main macromolecular components of the mucus secretions that cover the oral cavity, gastrointestinal and urogenital tracts of animals. The properties of the mucus secretions are therefore directly correlated with the physicochemical properties of mucin glycoproteins. In this study, mucins were obtained from pig gastric mucous after digestion with pepsin at 37°C for 4h, these mucins were characterised in terms of compositional and hydrodynamic properties. Compositional analysis showed that this mucin contains protein (15%), carbohydrates (55%) of which the constituents are: fucose (4%), galactose (9%), glucosamine (55%), glucosamine (33%) and sialic acid (2%). The latter component gives the mucin polymer a pH-dependant negative charge, with a ζ-potential of −3mV at pH 1.2 up to −11mV at pH 7.4. The weight average molar mass was ∼1×106g/mol and intrinsic viscosity was ∼0.42dL/g although there was a small pH dependency due to the polyelectrolyte behavior of the polymer. The measurements of viscosity versus shear rate showed shear thinning behavior and the critical overlap concentration was determined to be 10–11% w/v indicating a compact structure. Knowledge of these properties is fundamental to the understanding interactions of mucins, with for example, novel drug delivery systems.