RICHLAND, Wash. -- Inactive enzymes entombed in tiny honeycomb-shaped holes in silica can spring to life, scientists at the Department of Energys Pacific Northwest National Laboratory have found.
The discovery came after salvaging enzymes that had been in a refrigerator long past their expiration date. Enzymes are proteins that are not actually alive but come from living cells and perform chemical conversions.
To the research teams surprise, enzymes that should have fizzled months before perked right up when entrapped in a nanomaterial called functionalized mesoporous silica, or FMS. The result points the way for exploiting these enzyme traps in food processing, decontamination, biosensor design and any other pursuit that requires controlling catalysts and sustaining their activity.
Theres a school of thought that the reason enzymes work better in cells than in solution is because the concentration of enzymes surrounded by other biomolecules in cells is about 1,000 to 10,000 time more than in standard biochemistry lab conditions, said Eric Ackerman, PNNL chief scientist and senior author of a related study that appears today in the journal Nanotechnology. This crowding is thought to stabilize and keep enzymes active.
The silica-spun FMS pores, hexagons about 30 nanometers in diameter spread across a sliver of material, mimic the crowding of cells. Ackerman, lead author Chenghong Lei and colleagues said crowding induces an unfolded, free-floating protein to refold; upon refolding, it reactivates and becomes capable of catalyzing thousands of reactions a second.
The FMS is made first, and the enzymes are added later. This is important, the authors said, because other schemes for entrapping enzymes usually incorporate the material and enzymes in one harsh mixture that can cripple enzyme function forever.
In this study, the authors reported having functionalized the silica pores by lining them with compounds
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Contact: Bill Cannon
cannon@pnl.gov
509-375-3732
DOE/Pacific Northwest National Laboratory
28-Nov-2006