Abstract
pH sensitive dodecyl-modified poly(allylamine)s associate with superoxide dismutase (SOD) in aqueous solutions at pH 5.5 and 7.4. The bound SOD can be released completely at pH 10.0 due to the self-aggregation of the polymers. In a mixture of water and organic solvent, the hydrophobic groups of the polymers are exposed. During the process of removing the organic solvent, the polymers increase their hydrophobic interactions with SOD. As a result, the SOD binding of the polymers increases; the release of SOD from the complexes is remarkably extended. The released SOD molecules have full activity. The knowledge gained in this study will be beneficial to the applications of hydrophobically modified polyelectrolytes as delivery carriers for protein/peptide drugs.