Immobilization and Stabilization of the Pisum sativum Diamine Oxidase onto Chitosan-Modified Gold Electrode

Abstract

In this work, the diamine oxidase (DAO) produced from pea seedlings was partially purified using ammonium sulphate precipitation, dialysis, and gel filtration chromatography. Partially purified DAO was immobilized covalently with the help of a cross-linker glutaraldehyde onto the chitosan- modified gold electrode. The properties of immobilized enzyme were evaluated by optimum pH, optimum temperature, activity recovery, and recyclability using putrescine dihydrochloride as substrate. After immobilization of DAO, optimum pH ranges from 6.0 to 7.0 did not change and optimum temperature of enzyme changed from 34 to 38°C in comparison to free DAO. The immobilized DAO preserved 81% activity of free DAO and permitted increased stability and reusability of the enzyme than its native form. After 15 cycles of usage, the immobilized DAO maintained around 51% of its original activity, and this activity prolonged for 30 days at 4°C.