Nanowrapping cell enzymes: "To increase [a cell's] enzyme's longevity and versatility, a team at the Department of Energy's Pacific Northwest National Laboratory in Richland, Wash., has caged single enzymes to create a new class of catalysts called SENs, or single enzyme nanoparticles. The nanostructure protects the catalyst, allowing it to remain active for five months instead of hours. "The principal concept can be used with many water-soluble enzymes," said Jungbae Kim of PNNL..
Kim and Grate modified a common protein-splitting enzyme called alpha-chymotrypsin. They modified the enzyme surface to make it soluble, then added vinyl reagents to induce the growth of molecular threads, or polymers, from the enzyme surface. A second polymerization step cross-linked silicon chains, forming a basketball-netlike structure a few nanometers thick. What results are SENs that appear in electron microscopic images as hollow enzyme-containing nanostructures about 8 nanometers across. Kim and Grate found that by using less reactive forms of vinyl they could vary the thickness of the nano-netting by half. Thick or thin, the porous netting preserves the shape of the enzyme inside yet allows its active site to interact with a substrate. SENs are also amenable to storage; they have been refrigerated for five months, losing little of their activity.
Among the uses Kim noted for SENs is the breakdown toxic waste--a single treatment could last months. Stabilized enzymes are also a prerequisite for many types of biosensors. And they may be of interest for coating surfaces, with application ranging from medicine (protecting implants from protein plaques) to shipping (keeping barnacles off hulls)." 10:07:44 PM