Firefly luciferin, chemiluminescence

Later, fireflv oxyluciferin was successfully synthesi2ed (403. 408) and has been isolated and identified in firefly lanterns (luciola cruaciata) after the lanterns were treated with pyridine and acetic anhydride to prevent decomposition (409). In 1972, Suzuki and Goto firmly established that oxyluciferin is involved in the bioluminescence of firefly lanterns and in the chemiluminescence of firefly luciferin (403. 410).. A. mechanism involving a four-membered ring cyclic peroxide has been proposed for the reaction (406. 411). However, it was not confirmed by 0 -labelinE experiments (412). 

In the luminescence reaction of firefly luciferin (Fig. 1.12), one oxygen atom of the product CO2 is derived from the molecular oxygen while the other originates from the carboxyl group of luciferin. In the chemiluminescence reaction of an analogue of firefly luciferin in DMSO in the presence of a base, the analysis of the product CO2 has supported the dioxetanone pathway (White et al., 1975). 

One is the concerted decomposition of a dioxetanone structure that is proposed for the chemiluminescence and bioluminescence of both firefly luciferin (Hopkins et al., 1967 McCapra et al., 1968 Shimomura et al., 1977) and Cypridina luciferin (McCapra and Chang, 1967 Shimomura and Johnson, 1971). The other is the linear decomposition mechanism that has been proposed for the bioluminescence reaction of fireflies by DeLuca and Dempsey (1970), but not substantiated. In the case of the Oplopborus bioluminescence, investigation of the reaction pathway by 180-labeling experiments has shown that one O atom of the product CO2 derives from molecular oxygen, indicating that the dioxetanone pathway takes place in this bioluminescence system as well (Shimomura et al., 1978). It appears that the involvement of a dioxetane intermediate is quite widespread in bioluminescence. 

Seliger, H. H., and McElroy, W. D. (1962). Chemiluminescence of firefly luciferin without enzyme. Science 138 683-685. 

Suzuki, N., and Goto, T. (1971). Firefly bioluminescence. II. Identification of 2-(6 -hydroxy benzothiazol-2 -yl)4-hydroxythiazol as a product in the bioluminescence of firefly lanterns and as a product in the chemiluminescence of firefly luciferin in DMSO. Tetrahedron Lett. 22 2021-2024. 

Derivatives of synthetic firefly luciferin 172> and analogs thereof 173> were found to exhibit strong chemiluminescence (i.e. in contrast to... 

The yellow-green chemiluminescence of firefly luciferin is evidently dependent on the enol form of the thiazolinone 109a, for 5.5-dimethyl-luciferin 116a which does not yield an enolizable ketone does not exhibit a yellow-greenish emission on addition of excess base only red emission is observed. 

As mentioned earlier (see p. 122) the previously postulated dioxetane intermediate in firefly bioluminescence has been challenged as no 180 is in-corporated in the carbon dioxide released during oxidation of firefly luciferin with 18C>2. In view of the crucial significance of the 180. experiments De Luca and Dempsey 202> rigorously examined the reliability of their tracer method. They conclude from their experiments that all available evidence is in favour of a linear, not a cyclic peroxide intermediate — in contrast to Cypridina bioluminescence where at least part of the reaction proceeds via a cyclic peroxide (dioxetane) as concluded from the incorporation of 180 into the carbon dioxide evolved 202,203). However, the dioxetane intermediate is not absolutely excluded as there is the possibility of a non-chemiluminescent hydrolytic cleavage of the four-membered ring 204>. 

It must be pointed out that, despite the lack of direct experimental support for this hypothesis, the involvement of the electron transfer in luminol chemiexcitation is related to the chemiexcitation steps proposed for several highly efficient chemi- and biolu-minescent systems, such as activated peroxyoxalate chemiluminescence and the firefly luciferin/luciferase system (Section... 

Analogously to the firefly luciferin/luciferase system, the general chemiluminescence mechanism postulated for 9-carboxyacridinium derivatives proposes the 1,2-dioxetanone 45 as high-energy intermediate However, this 1,2-dioxetanone is the only intermediate that has not yet been isolated . The cleavage of the peroxidic ring presumably results in the release of CO2 and the formation of an acridan residue in its electronically excited state (Scheme 32). 

Several other examples of 1,2-dioxetane derivatives containing easily oxidizable groups have been reported and the high singlet quantum yield observed in their decomposition was attributed to the occurrence of the intramolecular CIEEL sequence Based on this concept, Schaap and coworkers have introduced the concept of induced chemiluminescence, which is very relevant for investigations into firefly luciferin bioluminescence and has led to the development of chemiluminescent probes widely used in immunoassays (Section N. 

CIEEL is of particular interest for the development of modern chemiluminescent bioassays. The most popular clinical bioassays utilize thermally persistent spiro-adamantyl-substituted dioxetanes with a protected phenolate moiety. These designed 1,2-dioxetanes include an energy source, a fluorophore, and a trigger grouping, and are therefore structurally similar to bioluminescent substrates such as firefly luciferin. Three main commercial dioxetanes 75 are available as one-reagent assays for alkaline phosphatase and are sold under the name of AMPPD (R1 = R2 = H), CSPD (R1 = Cl, R2 = H), and CDP-Star (R1 = R2 = Cl) <2006S1781, 2003ANA279>. These substrates are sensitive to 10 21 mol of alkaline phosphatase in solution. 

Bioluminescence is a unique type of chemiluminescence found in biological systems these reactions can be classified as either pyridine- or adenine-nucleotide linked systems or enzyme-substrate systems. In clinical enzymology, the most commonly used system is the firefly luciferin-luciferase system for the measurement of ATP ... 

The proposed reaction scheme of the chemiluminescence (CL) of firefly luciferin (Ln) is shown in Fig.l. 

Shibata R, Yoshida Y, Wada N. Filter-photometry of chemiluminescence from firefly luciferin intermediate M420 in deoxygenated dimethyl sulfoxide. J Photosci 2002 9 290-2. 

The quenching of peroxidized luminol chemiluminescence by reduced pyridine nucleotides has been reported. Neither superoxide nor hydroxyl radical scavengers were found to quench the chemiluminescence of luminol in the presence of horseradish peroxidase and H2O2. Both chemi- and bio-luminescence of firefly luciferin have been investigated and a dioxetanone mechanism proposed for the light-producing pathway. ... 

Oxygen-18 studies of the chemiluminescence of a firefly luciferin analogue have provided evidence which contradicts other earlier reports in that it suggests that the dioxetanone is an important intermediate in light production.304 Spin-statistical contributions in redox chemiluminescence quantum efficiency have been analysed,305 and a striking deuterium isotope effect in phosphorus chemiluminescence has been discovered.800... 

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