Adsorption of α-amylase onto poly(N-vinyl 2-pyrrolidone/itaconic acid) hydrogels

alpha-Amylase enzyme was adsorbed on poly(N-vinyl 2-pyrrolidone/itaconic acid) (P(VP/IA)) hydrogels prepared by irradiating the ternary mixtures of VP/IA/water by gamma-rays at ambient temperature. The adsorption capacity of the hydrogels was determined to increase from 2.30 to 3.40 mg alpha-amylase/g dry gel with increasing amount of IA in gel system. Kinetic parameters were calculated as 2.51 g/dm(3) for K-m and 1.67 x 10(-3) g/dm(3) mill for V-max for free enzyme and in the range of 3.88-5.02 g/dm(3) for K-m and 1.62 x 10(-3) - 2.27 x 10(-3) g/dm(3) min for V-max depending on the amount of IA in the hydrogel. Enzyme activities were found to increase from 49.9% to 77.4% with increasing amount of IA in the gel system and retained their activities for one month storage. On the other hand, the free enzyme loses its activity completely after 20 days. (C) 1999 Elsevier Science B.V. All rights reserved.