Scientists in the United States have come up with a new method for boosting enzymatic activity that helps enzymes remain active and fit, and to be utilized under a much greater variety of conditions. With enzymes being crucial for digestion, as well as in such things as drug manufacturing and even bread making, this work on stabilizing enzymes through nanopore confinement could offer a range of innovations in medicine, chemistry, biology, biofuels, and nanoengineering.
Enzymes are proteins that help to speed up (or catalyze) chemical reactions; however, when they are removed from their comfort zone of a cell or body, they often quickly lose their shape and become denatured. For example, when things go off, as in milk turning sour, enzymes are becoming denatured. Also, when enzymes are placed on a surface their activity is normally reduced. However, this study has revealed that when they are positioned inside the precisely engineered environment of nanoscale holes called nanopores, activity increases dramatically, meaning that enzymatic activity is very dependent on local environment.
With the wrapping of enzymes and other proteins in and around nanomaterials becoming an increasing important focal point of international research, the team found that the activity of the tested enzymes was higher when they were inserted into nanopores than when the same enzymes were in solution, under the same conditions. This is particularly significant, since earlier research suggested that the convex, positive curvature of the exterior of nanoparticles and nanotubes lowers enzymatic activity.
The new technique involves embedding lysozymes and other enzymes into a nanoporous material with a pore size of only 5 nm to 12 nm, so that they are able to keep their three-dimensional structure, as well as showing a substantial surge in activity and not denaturing. The study by researchers at the Rensselaer Polytechnic Institute, led by Marc-Olivier Coppens, and published in the journal Physical Chemistry Chemical Physics [Sang, L-C, Coppens, M-O, Phys Chem Chem Phys (2011) doi: 10.1039/c0cp02273j], explores how the lysozymes can be confined neatly into this compact space, so that the lysozyme finds it difficult to unfold or move around.
The ability to stabilize and increase enzymatic activity in a controllable but easy way through immobilization on the internal surface of nanoporous materials could help to increase the activity and selectivity of different enzymes. The team will also examine a range of techniques for identifying the fundamental mechanics of confined enzymes inside nanopores, such as multiscale modeling methods and molecular simulations.
Because many enzymes of practical use are so expensive, the ability to reuse them should bring about applications in biotechnology, the manufacture of pharmaceuticals, sensors for medical and environmental applications, and for drug delivery via a porous matrix.


Laurie Donaldson