STUDY ON THE THERMAL-STABILITY OF ALPHA-AMYLASE MODIFIED BY MALEIC-ANHYDRIDE COPOLYMER

The thermal inactivation of mesophilic Bacillus subtilis alpha-amylase modified by maleic anhydride/vinyl acetate copolymer has been studied at different polymer/enzyme ratios in the pH range of relevance to en zymatic catalysis. Enzymatic activity measurements combined with circu lar dichroism measurements were used to determine the enzyme thermosta bility. The apparent first-order rate constants and activation energie s of thermo-inactivation affected by addition of Ca2+ ions as well as by modification have been calculated. The modified alpha-amylase exhib ited sufficiently high catalytic activity with enhanced resistance to the thermal unfolding process.