Abstract

Bovine pancreatic trypsin was chemically modified by a β-cyclodextrin-carboxymethylcellulose polymer using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as coupling agent. The conjugate retained 110% and 95% of the initial esterolytic and proteolytic activity, respectively, and contained about 2 mol of polymer per mol of trypsin. The optimum temperature for trypsin was increased to 8°C after conjugation. The thermostability of the enzyme was increased to about 16°C after modification. The conjugate prepared was also more stable against thermal incubation at different temperatures ranging from 45°C to 60°C. In comparison with native trypsin, the polymer-enzyme complex was more resistant to autolytic degradation at pH 9.0, retaining about 65% of the initial activity after 3 h incubation. In addition, modification protected trypsin against denaturation in the presence of sodium dodecylsulfate.