Simple and rapid detection of l-Dopa decarboxylase activity using gold nanoparticles

We developed a new detection method for L-Dopa decarboxylase (DDC) activity using gold nanoparticles (AuNPs). When L-3,4-dihydroxyphenylalanine (L-Dopa) is decarboxylated to dopamine (DA) by DDC, DA induces the aggregation of AuNPs, and the color of the AuNPs changes from red to blue.