Esterase activity of cyclodextrin dithiocarbamates

The catalytic activity of dithiocarbamate appended α- and β-cyclodextrins in the hydrolysis of p-nitrophenyl acetate (PNPA) was studied at alkaline pH. The values of k_cat/k_uncat for the hydrolysis of PNPA ranged from 8 to 165 in the presence of the catalyst and are pH independent in the range 7.5-9.0. Addition of Cu(II) increases the activity by factors of 75-515 and k_cat values increase with increasing pH in the same range. The differences in the obtained kinetic parameters are interpreted on the basis of two different mechanisms.