A smart bioconjugate of trypsin with alginate.

Alginate is a polymer of guluronic acid and mannuronic acid residues and is an inexpensive, nontoxic polysaccharide of marine origin. Trypsin was immobilized noncovalently on alginate with 100% retention of activity. The enzyme did not leach off the polymer even in the presence of 0.01 M HCl and Triton X-100 (0.2% vv(-1)). The V(max)/K(m) values did not change significantly on immobilization. There was 22% loss of activity in first cycle of pH change and after that the conjugate could be reused upto 4 precipitation cycles without any further loss of activity. This smart bioconjugate was also found to have better operational stability in the presence of casein than free enzyme. Fluorescence studies were carried out to probe structural changes upon immobilization.