Nanoparticle support for enzymes

[nanoorg]

Nanoparticle support for enzymes

by Karen Rigby

Gold nanoparticles can stabilize enzymes at air-water interfaces, enhancing their applications as biocatalysts.

Vincent Rotello and colleagues at the University of Massachusetts at Amherst, US, used nano-sized particles as scaffolds to support and stabilise the enzyme chymotrypsin.

Chymotrypsin catalyses hydrolysis reactions. Like other enzymes, chymotrypsin has a natural tendancy to degrade at air-water surfaces, losing its structure and catalytic activity. Rotello and colleagues say the enzyme can be stabilized by surrounding it with monolayer-protected gold nanoparticles (MPNs). MPNs are spherical nano-structures in which gold nanoparticles are surrounded by a negatively-charged shell of tetra(ethylene glycol) carboxylate ligands.

According to Rotello, MPNs are roughly the same size as chymotrypsin (about 6 nanometres in diameter), and bind electrostatically to the enzyme in water. This stabilizes the enzyme by restricting its ability to unfold at the air-water surface.

‘The key finding is that we can stabilize proteins under conditions that would normally reduce or eliminate their activity,’ explained Rotello. ‘At the moment, each protein is a special case that requires a new answer. Once we understand the process, it should be much easier to tailor particles to stabilize specific proteins.’

Rotello said the findings are significant for technologies that use enzymes to catalyse reactions at air–water surfaces.

Qun Huo, an expert in nanomaterials at the Universtiy of Central Florida, US, noted the potential applications of Rotello’s research. ‘This is a very elegant approach of using nanotechnology to solve one of the long-standing problems in the biotechnology area,’ said Huo. ‘This work from Rotello’s group will have a significant impact in many areas such as biosensor development, where the stablilization of enzymes and proteins has been one of the key limiting factors in the field.’



Source and more information:

http://www.rsc.org/Publishing/ChemScience/




This story was first posted on 7th July 2006.