Covalent and noncovalent adducts of proteins with water-soluble poly(alkylene oxides)

Protein conjugates with PEG and amphiphilic block copolymers of ethylene oxide and propylene oxide (Proxanols) were synthesized. Four types of conjugates ranging in the placement of hydrophobic block and type of polymer chains distribution were obtained. In parallel methods of thermoinduced and high-pressure induced complexation were developed for the synthesis of non-covalent adducts between proteins and Proxanols. Covalent and noncovalent adducts based on alpha-chymotrypsin (CHT) retain high enzymatic activity. They were characterized by higher thermostability with regard to the native enzyme. Membranotropic properties of conjugates were demonstrated through the study of their translocation across the cell membrane of T-lymphocytes and the investigation of catalytic properties in hydrated reversed micelles. Conformational models of polymer-protein conjugates were suggested. It was assumed that conjugates form in aqueous solutions compact structures resembling intramolecular micelles.