[Synthesis of trypsin polymer derivatives with single-point binding of the polymer-modifier and protein]

In order to produce carbon-chain covalent "star-like" conjugates of trypsin, the latter was modified by attachment of fragments containing the reaction-capable azo-bond and then N-vinyl pyrrolidone was polymerized on the resultant high molecular weight initiator. The molecular weight and proteolytic activity of the compounds were determined, and their thermal stability and resistance to autolysis were investigated. It was shown that the trypsin modified by poly-N-vinyl pyrrolidone of different molecular weights acquired greater resistance to autolytic and thermal denaturation. The spectropolarimetric examination of the conformation properties of the modified trypsin forms at varying pH demonstrated that attachment of azo-bond containing fragments to the enzyme molecule destabilized its native structure in acidic pH areas while subsequent poly-N-vinyl pyrrolidone modification increased the area of pH-stability of the conjugate as compared to the native trypsin.