There is significant interest in using enzymes for a variety of applications such as in biotransformations and as fuel cell components. In general, enzymes offer excellent activity and substrate specificity; but unfortunately, require cofactors, buffered solutions, denature at high temperatures, and suffer from instability and short shelf-lifes. Nevertheless, the ability to harness this extraordinary level of activity has inspired efforts in genetic engineering of enzymes and production of inorganic enzyme mimics. In the following, we have mimicked the activity of the nitrate reductase enzyme by using peptide assembled CdS-Pt nanoparticles. Notably, these nanoparticles exhibit a 23-fold increase in activity as compared to nitrate reductase, enhanced thermal stability, and increased activity at 75 C.