In this work, highly luminescent ovalbumin-protected Au nanoparticles (OVA-Au NPs) with a quantum yield of 9.3% for emission at 645 nm were demonstrated as a fluorescence probe for sensitive detection of glucose. The fluorescence of the Au NPs originated from the Au(I)-thiol (S) complex on their surfaces, and it was found to be quenched effectively by enzymatically generated hydrogen peroxide (H2O2). The OVA-Au NPs allowed the determination of glucose concentrations in the range varying from 1.0 x 10(-4) to 1 x 10(-2) M with a detection limit of 1 x 10(-5) M.