Effect of Chitosan Degradation on Its Interaction with beta-Lactoglobulin

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Hileia K. S. Souza (Author) FEUP; Maria do Pilar Gonçalves (Author) FEUP; Javier Gómez Pérez (Author) Other

Journal

Title: Biomacromolecules

Vol. 12

Pages: 1015-1023

ISSN: 1525-7797

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 30 Citations

ISI Web of Science

Scopus - 31 Citations

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

Other information

Authenticus ID: P-002-SQ2

DOI: 10.1021/bm101356g

Abstract (EN): Complexes between chitosan and beta-lactoglobulin (beta-Lg) were investigated, and their formation was found to depend on pH and ionic strength. The electiostatic attraction between the cationic polysaccharide and the negatively charged protein above its isoelectric point has been identified as the main driving force in the molecular recognition process. At low protein concentration, soluble complexes were shown to be formed, and their structural features were characterized by circular dichroism (CD) and steady-state fluorescence. Both the overall secondary structure of the protein and the local environment probed by its tryptophan residues are not affected by the presence of chitosan in the complex. Furthermore, the formation of the complex does not lead to a net stabilization of the native state of the protein over its denatured state due to formation of a similarly stable.. complex between the polyelectrolyte and the denatured state of the protein. The formation of coacervates between beta-Lg and chitosan was also characterized as a function of average molecular weight of chitosan (subjected to ultrasonication for different periods of time: 0, 5, 15, and 30 min) by means of both turbidimetric and calorimetric techniques. The combination of turbidimetric as well as isothermal calorimetric titrations have allowed the deconvolution of two processes usually coupled in the formation of protein polyelectrolyte coacervates: the formation of complex coacervates as the protein sites become saturated by polyelectrolyte molecules and the redissolution of the coacervates as the polyelectrolyte-to-protein ratio increases.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9