Silver nanoparticles (AgNPs) are best known for its catalytic activity. With the current knowledge of biophysics and spectroscopy techniques, we have attempted to study the changes in the structure of amylase upon interaction with AgNPs. Alpha-amylase interacted with AgNPs were investigated by UV-visible, Fourier transform infrared (FTIR), fluorescence and circular dichroism (CD) spectroscopic techniques. UV-Vis spectra showed a plasmon shift towards the lower wavelength indicating structural changes with increased solvent exposure to Trp residues. FTIR studies revealed Ag O bond formation via Trp residues. Fluorescence spectral intensity pertaining to Tryptophan (Trp) residue decreased with an increase in AgNP concentration and a hypsochromic shift from 0.6 mM AgNP. The content of α-helix was decreased by 26.87% while the turns were increased by 49.5% as analyzed by CD studies. The enzyme activity of AgNP-amylase was assayed by Nelson-Somogyi method. AgNP-amylase showed higher catalytic activity with 10 times higher production of reducing sugars at a concentration of 0.6 mM AgNP within fifteen minutes. The conformational change in the structure of amylase had a potential for the higher enzymatic activity for starch breakdown. These studies revealed that the protein structure had changes from UV-Vis, FTIR, CD and fluorescence spectroscopy which helped in increasing the enzyme activity. Copyright © 2013 American Scientific Publishers. All rights reserved.