INTERACTION OF CROSS-LINKED SODIUM POLYACRYLATE WITH PROTEINS

Interaction of cross-linked sodium polyacrylate (PA) with proteins (cytochrome c, lysozyme, and protamine) was studied. It was established that lightly cross-linked polyacrylate gel is able to sorb proteins, carrying positive charge, within a wide range of pH and ionic strengths of the medium. As a result, an interpolymer complex forms in the gel phase, in which the protein species are connected by salt bonds to the regions of crosslinked sodium polyacrylate. The compositions of complexes and the number of salt bonds between carboxyl groups of the cross-linked polymer and amino groups of proteins were determined. The composition of complexes between cross-linked sodium polyacrylate and proteins is independent of the component ratio in the reaction mixture and corresponds-to the composition of insoluble complexes formed between linear sodium polyacrylate and these proteins. The sorption of proteins occurs at the front of the propagating heterogeneous reaction, which accounts for the possibility to obtain layered compositions comprising charged polymer networks and proteins.