The formation of non-soluble complexes between polyethyleneimine–anions and their potential use to isolate enzymes

CASSANE, C; BOERIS, V.; WAGNER, J.; BOERIS, V.; G, PICÓ

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2011 vol. 80 p. 354 - 358

0927-7765

The aqueous solution behavior of polyethyleneimine (a synthetic cationic polymer) in the presence of  anions with two or more electrical charges (citrate, phosphate, sulphate, malate, malonate and succinate)   was studied by means of turbidimetry and light scattering. Polyethyleneimine forms non-soluble  complexes with these anions, which behave as a pseudo-polyampholyte with an isoelectrical pH value  dependent on the type of anion. The effect of pH, polymer concentration and ionic strength on the nonsoluble  complexes formation was examined. The complex precipitation pH range was between 3.5 and  8.0 and also depended on the type of anion. The complex formation was inhibited by the ionic strength in  agreement with the electrostatic mechanism of the non-soluble complex formation. Model proteins with  isoelectric pH from 1 to 10 were assayed in orden to be precipitated by these complexes. It was found that  the non-soluble polyethyleneimine–anion complexes have the property to precipitate macromolecules  charged with an opposite electrical charge.