Chemical modification and thermal stability study of β-cyclodextrin- and PAMAM-trypsin conjugates

Bovine pancreatic trypsin conjugates were first synthesized using succinoylated beta-cyclodextrin and succinoylated PAMAM dendrimer. Their conjugates had a trypsin content of 72 and 50 wt%, respectively. The trypsin activity of conjugates measured by using Nalpha-benzoyl-D, L-arginine-p-nitroanilide hydrochloride (BAPNA) as substrate was decreased by polymer conjugation. The kinetic parameters (K_M, V_max and K_cat) were also calculated. The beta-cyclodextrin-trypsin conjugate was more stable than native trypsin and PAMAM-trypsin conjugate at all temperatures between 30-70degC. It also exhibited better thermal stability in the autolysis assays at 40degC.