STABILIZATION OF PROTEASES BY ENTRAPMENT IN A NEW COMPOSITE HYDROGEL

A new one-step procedure for entrapping proteases into a polymeric com posite calcium alginate-poly(N-vinyl caprolactam) hydrogel was develop ed that provided 75-90% retention of the activity of entrapped enzymes compared to soluble ones. Properties of entrapped carboxypeptidase B, trypsin, and thrombin were investigated. The immobilized enzymes were active within a wide pH range. The temperature optima of entrapped tr ypsin and carboxypeptidase B were approx 25 degrees C higher than that of the soluble enzymes, and the resistance to heating was also increa sed. The effects of various polar and nonpolar organic solvents on the entrapped proteases were investigated. The immobilized enzymes retain ed their activity within a wide concentration range (up to 90%) of org anic solvents. Gel-entrapped trypsin and carboxypeptidase (CPB) were s uccessfully used for obtaining human insulin from recombinant proinsul in. The developed stabilization method can be used to catalyze various reactions proceeding within wide pH and temperature ranges.