| Abstract: | Cathepsin B (EC 3.4.22.1), purified from goat brain, was immobilized in calcium alginate beads in the presence of bovine serum albumin. The immobilized enzyme retained ∼63% of the original activity and could be used for seven successive batch reactions with retention of 22–30% of the initial activity. Immobilized cathepsin B hydrolysed α-N-benzoyl-D ,L -arginine-β-naphthylamide (BANA) maximally at pH 5·5, exhibiting a shift of 0·5 pH unit from that of the soluble enzyme (pH optima 6·0). It showed enhanced stability in acidic as well as alkaline environments in comparison to the free enzyme. The optimal temperature and thermal stability were not altered significantly after immobilization. The Km value for the immobilized enzyme was two-fold higher than for the soluble enzyme. |
