Luciferase
Luciferase is an enzyme commonly used in nature for bioluminescence. In luminescent reactions, light is produced by the oxidation of a luciferin (a pigment), sometimes involving Adenosine triphosphate (ATP). The rates of this reaction between luciferin and oxygen are extremely slow until they are triggered by the presence of luciferase. The reaction is very energy efficient: nearly all of the energy input into the reaction is transformed into light. As a comparison, the incandescent light bulb loses about 90% of its energy to heat.
Luciferin and luciferase do not refer to a particular molecule. They are generic terms for a light-producing chemical and its associated regulatory compound, usually a protein. A wide variety of organisms regulate their light production using a luciferase. The most famous is the firefly, although it even exists in beings as different as the Jack-O-Lantern mushroom and many marine creatures. In some organisms, notably the click beetles, the color of light produced is determined by the amino acid sequence of the luciferase, even though they use the same luciferin.
Luciferase can be produced in the lab through genetic techniques, and has a wide variety of uses. Genes for luciferase can be genetically engineered into organisms so that they glow when exposed to the right luciferin. This allows visualization of certain biological processes, stages of infection, and provides other valuable sources of information. Mice, silkworms, and potatoes are just a few organisms that have already been engineered to produce the chemical. Luciferase can be used in blood banks to determine if red blood cells are starting to break down. Laboratories can use luciferase to produce light in the presence of certain diseases. The possibilities for uses for luciferase continue to expand.
One peculiar application of luciferase was when a team of students from the University of Hertfordshire made news with their proposal to genetically engineer christmas trees to glow without lights, using luciferase (in addition to other bioluminescent chemicals). Luciferin would be added to a fertilizer used for the tree, which would react with the luciferase that the tree produces on its own. Of course, the similarity of the name of luciferase with the Christian Lucifer is likely to discourage investment into the development of the trees, even though the use of a christmas tree has a pagan origin.
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