An enzymatic synthesis route to protein-wrapped gold nanoparticles is developed. Glucose oxidase (GOD) reduces Au(III) ion in the presence of beta-D-glucose, and stable gold nanoparticles with average diameter of 14.5 nm are formed. FT-IR spectra, zeta potential and CD spectra of purified nanoparticles indicate that they are stabilized by the adsorbed protein layer.