In Vitro effects of metal oxide nanoparticles on barley oxalate oxidase

N. Chauhan, V. Hooda, C.S. Pundir
M.D. University, Rohtak, IN

Keywords: barley, oxalate oxidase, zinc-oxide nanoparticle, copper-oxide nanoparticles, manganese-oxide nanoparticles

Summary:

Barley oxalate oxidase (OxO), a manganese containing protein is largely employed for determination of oxalate in various biological materials. The present report describes in vitro effects of nanoparticles (NPs) of three metal oxides i.e. zinc oxide (ZnO), copper oxide (CuO) and manganese oxide (MnO2) on the activity and stability of OxO purified from barley roots. The transmission electron microscopy (TEM) and X-ray diffraction studies of these NPs revealed their very fine crystalline structure with the dimeter range 30-70 nm, 50-60 nm and 20-60 nm for ZnONPs, CuONPs and MnO2NPs respectively. The addition of suspension of these three NPs into assay mixture of enzyme resulted into adsorption of enzyme over the surface of metal oxides NPs as confirmed by scanning electron microscopy (SEM), fourier transform infrared spectra (FTIR) and UV-vis spectroscopic studies. Compared to free enzyme MnO2NPs bound enzyme showed improved activity (35% stimulation at 2.5 mg/ml concentration), while ZnONPs and CuONPs bound enzyme had no substantial improvement. The kinetics properties of individually NPs bound enzyme were studied and compared with those of free enzyme. The MnO2NPs bound enzyme showed marked improvement in its storage and thermal stability compared to free enzyme.