Enzyme chemiluminescent reactions catalyzed

Bacterial concentrations have also been determined by using the enzyme-catalyzed chemiluminescent reaction of reduced flavin mononucleotide (FMN) with oxygen and aldehydes. The detection limit was reported to be 10 ceUs of E. coli, which contains 7 x 10 g of FMN per ceU (303). 

Recently, two major enzyme-catalyzed chemiluminescent reactions have become popular. These use either luminol as a substrate of peroxidase or 3-(2 -spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)phenyl-1,2-dioxetane (AMPPD) as a substrate of alkaline phosphatase (ALP). 

Chemiluminescence results from reactions with a very high energy yield, which produce a potentially fluorescent product molecule reaction energy passed to the product may result in an excited state and subsequent production of a single photon of light. The light yield is usually low, but can approach one photon per molecule in bioluminescent reactions catalyzed by dedicated enzymes. 

II. The antigen is coupled with an enzyme, which catalyzes the chemiluminescence reaction of an appropriate compound plus an oxidant. 

Special review articles published since 1968 on these topics are one by E. H. White and D. F. Roswell 2> on hydrazide chemiluminescence M. M. Rauhut 3) on the chemiluminescence of concerted peroxide-decomposition reactions and D. M. Hercules 4 5> on chemiluminescence from electron-transfer reactions. The rapid development in these special fields justifies a further attempt to depict the current status. Results of bioluminescence research will not be included in this article except for a few special cases, e.g. enzyme-catalyzed chemiluminescence of luminol, and firefly bioluminescence 6>. 

The bioluminescence of the American firefly (Photinus pyralis) is certainly the best-known bioluminescent reaction, thanks to the work of Me Elroy and coworkers and E. H. White and his group (for references see P, p. 138, 6,168,169)) The substrate of this enzyme-catalyzed chemiluminescent oxidation is the benzothiazole derivative 107 (Photinus luciferin) which yields the ketone 109 in a decarboxylation reaction. The concept of a concerted cleavage of a dioxetane derivative has been applied to this reaction 170> (see Section II. C.). Recent experiments with 18C>2 have challenged this concept, as no 180-containing carbon dioxide was detected from the oxidation of 107 171>. 

Catalytic oxidation of isobutyraldehyde with air at 30—50°C gives isobutyric acid [79-31-2] in 95% yield (5). Certain enzymes, such as horseradish peroxidase, catalyze the reaction of isobutyraldehyde with molecular oxygen to form triplet-state acetone and formic acid with simultaneous chemiluminescence (6). 

The amount of substrate transformed into products during an enzyme-catalyzed reaction can be measured with any appropriate analytical method, such as spectrophotometry, fluorometry, or chemiluminescence. For example, if an enzyme reaction is accompanied by a change in the absorbance characteristics of some component of the assay system, in either the visible or ultraviolet spectrum, it can be photometrically observed while it is proceeding. Self-indicating reactions of this type are particularly valuable as... 

A familiar example of chemiluminescence is the light emitted by a firefly. In the firefly reaction, an enzyme, luciferase, catalyzes the oxidative phosphorylation reaction of luciferin with adenosine triphosphate to produce oxyluciferin, carbon dioxide, adenosine monophosphate, and light. Chemiluminescence involving a biological or enzyme reaction is often termed bioluminescence. The popular light stick is another familiar example of chemiluminescence. 

Immobilized L-amino acid oxidase catalyzes the oxidation of L-amino acids to 2-oxo acids. Detection of the hydrogen peroxide product is accomplished using a fluorometric or chemiluminescent assay subsequent to the reaction in the packed bed. L-Amino acids can also be quantified amperometrically using a platinum electrode Ag/AgCl on which the enzyme is... 

Horseradish peroxidase (HRP) is an archetypal heme peroxidase. It is a nonspecific enzyme used for studying the etfect of various substances on HRP-catalyzed electron-transfer reactions.1 2 For the enzyme activity determinations, many substrates and types of methods are used. One of these methods is lumino 1-dependent chemiluminescence (CL). The combination of the enzyme HRP/hydrogen peroxide (H202) system and a chemiluminescent method of detection allows for information to be obtained both about the result of the process and its course. 

Of comparable general importance is the bacterial luciferase system [226-228], which opens up the opportunity to combine any NAD(P) " -dependent enzyme-catalyzed reaction with a luminometric measurement. Even the chemiluminescent luminol reaction can be used for biosensing, because it can be coupled to any oxidase reaction that produces HjOj [225, 229]. The logical further development of these systems towards real optical biosensors has recently been reported by Blum et al. [230], who immobilized the light-producing systems onto the tip of optical fibers and thus obtained fiber-optic luminescence probes. 

Horseradish peroxidase (HRP) is also used for the detection of toxic compounds. A chemiluminescence test based on the reaction of luminol and an oxidant in the presence of the enzyme HRP has been developed to indicate the presence of toxins in a sample. The HRP-catalyzed reaction produces light that is measured by a lumi-nometer or a luminescence transducer. This enzyme has been used to detect a range of compounds such as phenols, amines, heavy metals, or compounds that interact with the enzyme, reduce light output, and indicate contamination. Test kits such as the Eclox Water Test Kit (Seven Trent Services, U.K.) is based on the use of HRP in the test format described earlier. This type of test is designed for the qualitative assessment of water samples for a range to compounds that inhibit the HRP activity. 

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