Available online at www.pelagiaresearchlibrary.com Pelagia Research Library European Journal of Experimental Biology, 2012, 2 (3):475-483 ISSN: 2248 –9215 CODEN (USA): EJEBAU 475 Pelagia Research Library The possible involvement of Nitrate Reductase from Asparagus racemosus in Biosynthesis of Gold Nanoparticles Sunil Pandey, Goldie Oza, Arvind Gupta, Ritu Shah, Madhuri Sharon* N. S. N. Research Centre for Nanotechnology and Bionanotechnology, Jambhul Phata, Ambernath (W), Maharashtra, India ______________________________________________________________________________ Abstract The green nanotechnological approach for the biosynthesis of gold nanoparticles by exploiting the reducing and thermodynamically efficient molecular mechanisms of medicinal plant Asparagus racemosus is reported in the present work. The most influential parameter was found to be temperature. At lower temperature (30ºC) the other optimum parameters were pH 8 and 100 ppm of aurochlorate salt; whereas at higher temperature (100ºC) the optimum parameters were pH 6 , 100 ppm of aurochlorate salt. The involvement of Glutathione as one of the capping proteins and nitrate reductases as possible reducing agent was confirmed by FTIR and biochemical assays respectively. The nitrate reductase activity was found to be reduced from 0.8293 μmole/min/gram to 0.6654 μmole/min/gram after bio fabrication of gold nanoparticles. Similarly, capping protein assay of Asparagus racemosus showed that total protein concentration in leaf extract was 17.14 μg/ml and its concentration was reduced after biofabrication of GNPs. The morphology and the crystal structure of the gold nanoparticles (GNP) were studied using electron microscopy and XRD respectively. Keywords: Asparagus racemosus, Biosynthesis, Gold-nanoparticle, Nitrate reductase, Glutathione. ______________________________________________________________________________ INTRODUCTION Bio-synthesis of metal nanoparticles, exploiting biological systems as an efficient sink has grabbed exceptional attention. Due to their novel optical [1], chemical [2], photoelectrochemical [3], and electronic [4] properties, there has been many chemical protocols developed by material scientists. Plethora of physical, chemical and biological processes results in the synthesis of nanoparticles, some of these are novel and others are quite common. Unlike chemical protocols which demands expensive instruments and results in release of inimical chemicals, biological method is more facile, eco-friendly and results in more monodispersed nanoparticles [5]. Nature has developed variety of processes for the biosynthesis of nano-scaled inorganic materials which are cardinal additions to the development of relatively new and largely un-charted area of research based on the biosynthesis of nanomaterials [6]. The synthesis and assembly of nanoparticles would benefit from the development of clean, harmless and environmentally acceptable ‘‘green chemistry’’ protocols, perhaps involving organisms ranging from bacteria to fungi and even plants [6]. Hence, both unicellular and multi-cellular organisms are known to fabricate inorganic materials either intra-or extracellularly [7]. Many plants are known to produce nanostructured mineral crystals and metallic nanoparticles with properties similar to chemically synthesized materials, while exercising strict control over size, shape and composition of the particles. Pandey and co-workers exploited the reducing potential of A.vasica [8] for tuning the parameters for GNPs formation. They also quantified the activity of nitrate reductase involved in catalyzing the nanoparticle biosynthesis.