Inhibition effect of some chemical on lactoperoxidase and covalently immobilized on a biocomposite for biosensor

Abstract

Lactoperoxidase was purified from bovine milk using ammonium sulfate precipitation and affinity chromatography. The greatest purification fold for lactoperoxidase has been obtained as 1302.65 folds with 24.95 % yields. The purity of the enzyme has been checked by SDS-PAGE and a single band has been detected corresponding to 78 kDa. IC50 values, Ki values and inhibition types were found for some chemicals on lactoperoxidase. Concentration range of chemicals is 1.0-10.0 x10(-6) M. The activity of asetophenone had very strong inhibitory effects with IC50 values of 1.82x10(-6) M. Asetophenone was determined mixed type inhibition with 5.46x10(-6) M Ki value using 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) as a substrate.

The enzyme was covalently immobilized onto a composite consisting of chitosan and gelatin biopolymers. The immobilization process was prepared on a glass substrate, a quartz crystal and an interdigitated electrode surface. This study will be a novel biosensor for based on measurements of pollutants, making it a selective and sensitive environmental pollutants in the water.