Invertase was immobilized onto the dimer acid-co-alkyl polyamine after activation with 1,2-diamine ethane and 1,3-diamine propane. The effects of pH, temperature, substrate concentration, and storage stability on free and immobilized invertase were investigated. Kinetic parameters were calculated as 18.2 mM for K-m and 6.43 x 10(-5) mol dm(-3) min(-1) for V-max of free enzyme and in the range of 23.8-35.3 mM for K-m and 7.97-11.71 x 10(-5) mol dm(-3) min(-1) for V-max of immobilized enzyme. After storage at 4degreesC for 1 month, the enzyme activities were 21.0 and 60.0-70.0% of the initial activity for free and immobilized enzyme, respectively. The optimum pH values for free and immobilized enzymes were determined as 4.5. The optimum temperatures for free and immobilized enzymes were 45 and 50degreesC, respectively. After using immobilized enzyme in 3 days for 43 times, it showed 76-80% of its original activity. As a result of immobilization, thermal and storage stabilities were increased. The aim of this study was to increase the storage stability and reuse number of the immobilized enzyme and also to compare this immobilization method with others with respect to storage stability and reuse number. (C) 2004 Wiley Periodicals, Inc.