Sandbox Reserved 951: Difference between revisions
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==Biological role== | ==Biological role== | ||
Firefly, also named Photinus pyralis, is a bioluminescent insect. They are able to produce light by a very energetic process, in order to attract its mate. The enzyme responsible of this light producing is luciferase, also known as luciferin-4-monooxygenase (EC: 1.13.12.7). | Firefly, also named Photinus pyralis, is a bioluminescent insect. They are able to produce light by a very energetic process, in order to attract its mate. The enzyme responsible of this light producing is luciferase, also known as luciferin-4-monooxygenase (EC: 1.13.12.7). It has various applications in the biotechnology field. In fact, it is used in chemical biology and drug assays. For example, they help to detect protein-protein interactions, to track cells in vivo in order to analysis in real-time the development of a disease in molecular level, to monitor the transcriptional and post-transcriptional regulation of specifics gens, to control apoptosis, to label cancer cells, to detect environmental contamination, to follow protein trafficking, … As there is no light production by mammals, luciferase is a really a great tool for researchers. But this light emission depends on the environmental conditions. Luciferase acts also as a ligase. | ||
Thus, this oxydo-reductase is involved in severals reactions. | |||
=====Light emission===== | =====Light emission===== | ||
The most known reaction of luciferase is the light emission. In this reaction, luciferase firstly synthetized luciferin-AMP from luciferin and ATP, using a Mg2+ ion to offset the negative charges of the phosphate groups. Then, luciferase turns the luciferin-AMP into oxyluciferin in an excited state thanks to a dioxygen. This step releases AMP and CO2. The excited oxyluciferin relaxes and looses a photon so light is emitted. | The most known reaction of luciferase is the light emission. In this reaction, luciferase firstly synthetized luciferin-AMP from luciferin and ATP, using a Mg2+ ion to offset the negative charges of the phosphate groups. Then, luciferase turns the luciferin-AMP into oxyluciferin in an excited state thanks to a dioxygen. This step releases AMP and CO2. The excited oxyluciferin relaxes and looses a photon so light is emitted. | ||
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=====Luciferin & Coenzyme A===== | =====Luciferin & Coenzyme A===== | ||
It has been found that the reaction between luciferin and CoA is possible, forming in a first step luciferin-AMP and then luciferin-CoA. This reaction leads to an interesting biological phenomenon : when this reaction occurs in parallel of light emission reaction, we don't have a flash of light but a continuous light emission. This is because luciferin-AMP is a competitive inhibitor of the reaction whereas the luciferin-CoA is not. So the inhibition is deleted and the reaction continue to occur. | It has been found that the reaction between luciferin and CoA is possible, forming in a first step luciferin-AMP and then luciferin-CoA. This reaction leads to an interesting biological phenomenon : when this reaction occurs in parallel of light emission reaction, we don't have a flash of light but a continuous light emission. This is because luciferin-AMP is a competitive inhibitor of the reaction whereas the luciferin-CoA is not. So the inhibition is deleted and the reaction continue to occur. | ||
