One-to-one laccase–gold nanoparticle conjugates: molecular recognition and activity enhancement

Abstract

A new method for the immobilization of one equivalent of a Trametes versicolor laccase per gold nanoparticle (d = 7.1 nm) is reported. The gold nanoparticles (AuNP) were capped with a self-assembled monolayer (SAM) of N-(11-mercaptoundecanoyl)tyrosinamide (MUATyr). The presence of the terminal Tyr moiety served as the molecular recognition site for the enzyme. Determination of the Cu/Au ratio by atomic absorbance spectroscopy (AAS) indicated the presence of one molecule of enzyme per particle. An enhancement of the thermostability and enzymatic activity of the immobilized enzyme was observed when compared with covalent binding through the terminal amino group of laccase.