αchymotrypsin catalyzed hydrolysis of n-benzoyl-l-tyrosine ethyl ester anchored in βcyclodextrin

N-Benzoyl-L-tyrosine ethyl ester, a substrate for αchymotrypsin (EC. 3.4.21.1) was solubilised by βcyclodextrin at a molar ratio of 1.0:2.0 but not by αcyclodextrin. The completely water soluble BTEE-βcyclodextrin complex served as an excellent substrate for the enzyme αchymotrypsin. The rate of hydrolysis of such a cyclodextrin anchored BTEE was identical to that of the substrate in Triton X-100 micelles, but was higher than the methanol solubilised substrate. The pH-activity profile was similar for all the three substrate preparations. The specificity constant (k_cat/K_m) was higher in the case of BTEE-βcyclodextrin compared to the methanol and Triton X-100 solubilised substrates. However, the enthalpy of activation was found to be increased in the case of Triton X-100 and βcyclodextrin anchored substrates.