ABSTRACT
Bioluminescence is light emission from the living organisms based on chemiluminescent reaction, catalyzed by specific enzyme - luciferase. Bioluminescence originates from oxidation of an organic substrate called luciferin in the presence of enzyme luciferase. Luciferin and luciferase are collection-functional rather than structure-functional types that indicate substrates and enzymes, interacting with one other and emitting light, simultaneously. The emission of light energy in chemical and biological processes is observed rather frequently, especially in the reactions with free radicals, however, in the most cases, the quantum yield (the number of light quanta emitted on the oxidation of one molecule of a substrate) is not higher than tenth or thousandth percent. The distinctive feature and the great advantage of bioluminescent systems is the high quantum yield (from 1 to 100%), which is explained by the participation of special proteins and enzymes in the reaction. On the one hand, luciferases act as a matrix, which is covalently or non-covalently bound to emitting chromophore, and, on the other hand, they play the role of biocatalysts that makes possible formation of electron-excited product. In most cases, the exclusively specific organization of protein structures in bioluminescent systems makes strict demands on the structure of luciferase substrates. Apparently, this is necessary for the maximum concentration of the enzymatic reaction energy on chromophore and formation of the electron-excited reaction product, which then returns to the basic state with the emission of the quantum of visible light.
