(Investigation the effect of H2O2 and pH on stability of recombinant Lepidium draba peroxidase (LDP

A very useful and important group of nanoparticles are magnetic nanoparticles (MNPs) that used to stabilize enzymes, due to of its unique features such as superparamagnetism, high surface-to-volume ratio, easy separation by external magnetic field, and etc. Enzymes stability (against the substrate, PH, temperature, and etc) and activity can be increase by immobilization. Enzyme peroxidase is a group of oxidoreductases, and this is a protein containing both hem and calcium ion as a prostatic group. HRP is one of the most used peroxidases; this enzyme is widely used in the manufacture of amperometric biosensors for the determination of organic and inorganic materials and H2O2. Also used in the treatment of cancer, the differentiation of stem cells and immunoassay, diagnosis, and etc. In this study, the effect of H2O2 and pH were investigated on stability of lepidium draba peroxidase (LDP). In the first stage, after bacterial culture containing plant peroxidase genes LDP and its expression was induced by IPTG, protein purification was performed using nickel-Sepharose column. The protein concentrations were 0.058 mg/ml and 0.071 mg/ml for H2O2 and pH. Respectively. Finally, the stability of free protein and protein treated with Fe3O4 NP (0.9 mM) for 4 hours at room temperature was studied with concentrations of H2O2 (0-14 mM) for 4h at 4ºC and range pH (3-7.25). The results showed that the stability of free protein and protein treated with nanoparticles against H2O2 has not changed, but the stability of enzymes treated with nanoparticle at various pHs is higher than that of free protein.