Mechanism of Luminescence Reaction

The biochemical mechanism of bacterial luminescence has been studied in detail and reviewed by several authors (Hastings and Nealson, 1977 Ziegler and Baldwin, 1981 Lee et al., 1991 Baldwin and Ziegler, 1992 Tu and Mager, 1995). Bacterial luciferase catalyzes the oxidation of a long-chain aldehyde and FMNH2 with molecular oxygen, thus the enzyme can be viewed as a mixed function oxidase. The main steps of the luciferase-catalyzed luminescence are shown in Fig. 2.1. Many details of this scheme have been experimentally confirmed. 

The deprotonated flavin in the complex is readily attacked by molecular oxygen at C4a, giving 4a-hydroperoxide of the flavin-luciferase complex (intermediate A). This complex is an unusually stable intermediate, with a lifetime of tens of seconds at 20°C and hours at subzero temperatures, allowing its isolation and characterization (Hastings et al., 1973 Tu, 1979 Balny and Hastings, 1975 Vervoort et al., 1986 Kurfuerst et al., 1987 Lee et al., 1988). 

In the presence of a long-chain fatty aldehyde, intermediate A (Fig. 2.1) is converted into intermediate B that contains a perox-yhemiacetal of flavin (Macheroux et al., 1993). The apparent Km value of the intermediate B produced with an aldehyde of 10-13 carbon atoms is approximately 200 pM when P. phosphoreum luciferase is used (Watanabe and Nakamura, 1972), and 1-10 pM when P. fischeri luciferase is used (Spudich and Hastings, 1963 Hastings and Nealson, 1977). The decomposition of intermediate B, 

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Mechanism of luminescence reaction. The chemical reaction of Oplophorus bioluminescence can be represented by the following simplified scheme ... 

The present book describes all the significant studies and findings on the chemistry of the more than 30 different bioluminescent systems presently known, accompanied by over 1000 selected references. It includes descriptions of the purification and properties of bioluminescent compounds, such as luciferins, luciferases and photoproteins, and the mechanisms of luminescence reactions. To make the book more useful than a mere review volume and to save researchers time in looking into original references, I have included a considerable amount of original experimental methods, data and graphs. In addition, I have included some new data and experimental methods unavailable elsewhere. I hope this volume will be useful to researchers and students, and it will be my greatest pleasure if this book contributes... 

It was suggested that the mechanism of this reaction can be explained on the basis of a "chemically initiated electron exchange luminescence (CIEEL)" (49,50) according to the following scheme ... 

Apart from these methods, pulse radiolysis, ESR and NMR spectroscopy, mass spectrometry, optical, chromatographic, and luminescent methods are also used. To study the kinetics and mechanism of the reactions in the early stages of polymerization pulse radiolysis with spectroscopic detection is often used [2-4],... 

Function of ATP in the ATP-dependent luminescence reaction catalyzed by the arm-organ extract. The amounts of coelenteramide disulfate, AMP and ADP produced in luminescence reaction under the conditions of standard assay were measured by HPLC. In this experiment, the luminescence reaction mixture had initially contained 4 nmol of coelenterazine disulfate and 250 nmol of ATP, and after 10 min of luminescence reaction, 0.58 nmol of coelenteramide disulfate, 0.1 nmol or less of AMP, and 15 nmol of ADP were found. Thus the molar amount of AMP produced is much less than that of coelenteramide disulfate, indicating that the production of AMP is unrelated to the luminescence reaction. Therefore, the mechanism of ATP-dependent luminescence reaction suggested by Tsuji that involved the formation of adenyl coelenterazine disulfate as a key intermediate, must be incorrect. 

Chemi- and bio-luminescence phenomena have been attractive not only from the scientific interest concerning with their molecular mechanisms but also from analytical, clinical, and for other various useiul applications. Many theoretical studies have been performed to elucidate detailed mechanisms of chemi- and bio-luminescence reactions. In past decades, our group has carried out both broken-symmetry (BS) and symmetry-adapted (SA) molecular orbital (MO) studies to clarify the electronic mechanisms of these reactions. Here, our basic concepts and methodologies, together with computational results, are briefly summarized. 

Since then, tremendous efforts have been made to elucidate the mechanism of this complex, multi-component luminescence reaction... 

The luminescence reaction of coelenterazine is initiated by the peroxidation of coelenterazine at its C2 carbon by molecular oxygen (Fig. 3.3.4). Then, the peroxidized coelenterazine decomposes into coelenteramide plus CO2, producing the energy needed for the light emission. For the mechanism of the decomposition of peroxide that produces the energy, two different pathways can be considered. 

Deng et al. (2004a,b) prepared the crystals of the spent obelin (W92F mutant from O. longissima) that had been luminesced with Ca2+, and successfully obtained the X-ray structure of apoobelin as an important information in elucidating the mechanism of the luminescence reaction. 

Harvey (1952) demonstrated the luciferin-luciferase reaction with O. phosphorea collected at Nanaimo, British Columbia, Canada, and with O. enopla from Bermuda. McElroy (1960) partially purified the luciferin, and found that the luminescence spectrum of the luciferin-luciferase reaction of O. enopla is identical to the fluorescence spectrum of the luciferin (A.max 510 nm), and also that the luciferin is auto-oxidized by molecular oxygen without light emission. Further investigation on the bioluminescence of Odontosyllis has been made by Shimomura etal. (1963d, 1964) and Trainor (1979). Although the phenomenon is well known, the chemical structure of the luciferin and the mechanism of the luminescence reaction have not been elucidated. 

Shimomura, O., Johnson, F. H., and Morise, H. (1974b). Mechanism of the luminescent intramolecular reaction of aequorin. Biochemistry 13 3278-3286. 

Firefly bioluminescence, 3-19 characteristics, 12 color of luminescence, 12 effect of pH, 13 effect of temperature, 14 factors required, 3, 4 light emitter, 17-19 mechanism, 15-17 overall reaction, 5... 

In the luminescence systems that require a peroxide or an active oxygen species in addition to molecular oxygen (the scaleworm, the tube worm Chaetopterus, the clam Pholas, the squid Symplecto-teuthis), their in vitro luminescence reactions reported are much slower and inefficient compared to their bright in vivo luminescence. The true, intrinsic activation factor in their in vivo luminescence should be determined, and the detailed mechanisms of oxidation should be elucidated. 

Luminescence yields data that often cannot be provided by any other methodology. This book is a compilation of a wide variety of original research contributions. Substantial information is given on the use of luminescence techniques to understand specific cell responses and the chemical mechanisms of cell action. An examination of natural environments is presented in the form of specific studies that characterize materials in both solid and liquid form and give information on the respective reactions of these materials in soil and water systems. Advanced research on standardization and standards developed for luminescence studies, as well as both active and passive use of luminescence, is included. 

Other speculative mechanisms [26] may be proposed based on the presence of singlet oxygen and C = C in oxidized polymer. The reaction of the latter may lead to the transient formation of dioxetanes, the decomposition of which has an even higher quantum yield of luminescence than CIEEL mechanism [27],... 

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