Enzyme-gold nanoparticle bioconjugates: quantification of particle stoichiometry and enzyme specific activity.

Enzyme-gold nanoparticle bioconjugates have a wide variety of uses ranging from nanoreactors to sensors and model systems. While easy to make, these bioconjugates are often not well characterized. This protocol outlines preparation of enzyme-nanoparticle bioconjugates and two complementary methods for quantifying enzyme:nanoparticle stoichiometry from which the specific activity of the adsorbed enzymes can be determined. Characterizations such as these can aid researchers in improving the design and application of future bioconjugate systems.