title: Interaction and complex formation between catalase and cationic polyelectrolytes: chitosan and Eudragit E100.
abstract: Interactions between catalase and the cationic polyelectrolytes: chitosan and Eudragit E100 have been investigated owing to their scientific and technological importance. These interactions have been characterized by turbidimetry, circular dichroism and fluorescence spectroscopy. It was found that the catalase conformation does not change significantly during the chain entanglements between the protein and the polyelectrolytes. The effects of pH, ionic strength and anions which modify the water structure were evaluated on the polymer-protein complex formation. A net coulombic interaction force between them was found since the insoluble complex formation decreased after the NaCl addition. Both polymers were found to precipitate around 80% of the protein in solution. No modification of the tertiary and secondary protein structure or the enzymatic activity was observed when the precipitate was dissolved by changing the pH of the medium. Chitosan and Eudragit E100 proved to be a useful framework to isolate catalase or proteins with a slightly acid isoelectrical pH by means of precipitation.
authors.affiliation: Bioseparation Lab. Chemical-Physics Department, Faculty of Biochemical and Pharmaceutical Sciences, CONICET, FonCyT and CIUNR, National University of Rosario, Suipacha 570 (S2002RLK) Rosario, Argentina.
authors.forename: Valeria
authors.initials: V
authors.lastname: Boeris
authors.forename: Diana
authors.initials: D
authors.lastname: Romanini
authors.forename: Beatriz
authors.initials: B
authors.lastname: Farruggia
authors.forename: Guillemo
authors.initials: G
authors.lastname: Picó
mesh_terms: D000179:Acrylates / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002374:Catalase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002417:Cattle; D011232:Chemical Precipitation; D048271:Chitosan / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D004795:Enzyme Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009391:Nephelometry and Turbidimetry; D011073:Polyamines / Q000737:chemistry* / Q000378:metabolism; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013696:Temperature; D017186:Titrimetry
chemical_list: D000179:Acrylates; D002374:Catalase; D048271:Chitosan; D011073:Polyamines; D000071228:Polyelectrolytes; D011108:Polymers; C477020:Eudragit E100