Thursday, April 19, 2012

Light helps enzymes do their work faster

Most of the processes in our body are sped up by enzymes. Without them, we would be unable to function, as enzymes are facilitators of chemical processes we require to allow our cells to do their job. By catalysing the breakdown of all sorts of molecules enzymes help us maintain metabolism, for example. They already greatly speed up anything that happens in our body, but scientists from Oak Ridge National Laboratory have found a way to make them work as much as 3000 times faster. Utilizing their technique, we may be able to alter chemical processes for our own benefit, which can have big consequences.

Structural changes
Looking at how the eye works, scientists have learned that light can change the structure of enzymes. For this, a light-sensitive molecule called rhodopsin is required, which allows for signals to travel to the brain, enabling vision. At the Oak Ridge National Laboratory, they developed a similar model by attaching light-sensitive molecules to enzymes. This would give us ways to modify an enzyme's activity at will, by hitting it with the correct beam of light.

Enzymes connect to their targets, called substrates, by binding them to a specific area on the molecular surface. This so-called active site is important if you want to improve the catalytic effect of an enzyme; the scientists used computer models to uncover regions on the molecular surface that impact efficiency, and how structural changes on these areas can lead to an increase or decrease. What they found is the required mechanical energy to make an enzyme called CALB more efficient by 8-52 fold. CALB functions by breaking down fat, which makes it easy to see how increased activity can be beneficial.
CALB was modified with the addition of a light-sensitive molecule called azobenzene, which made the enzyme perform better when hit with the correct beam of light. These modifications could eventually make enzymes do their job 3000 times faster, even though the CALB enzyme did not show such a large increase in activity. Future experiments should further optimize enzyme activity.

We use enzymes for production of various products, such as fuel or insulin. Large containers of cells or bacteria are often used as manufacturers, which could be made to work harder by modifying their enzymes and activating them with light. Perhaps we can also make our own bodies more efficient, but the scientists are focussing primarily on industrial applications.

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