Generation of Electronically Excited States in Situ. Polymorphonuclear Leukocytes Treated With Phenylacetaldehyde

Nascimento, Ana L. T. O.; Cilento, Giuseppe

doi:10.1111/j.1751-1097.1987.tb04747.x

Cited by 22 publications

(6 citation statements)

References 22 publications

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“…Chemiluminescence has been used in the past as evidence for excited species, , which we find in our reaction upon the thermal decomposition of the peroxy intermediate. Here, we find that in the presence of O 2 , a peroxy intermediate is photochemically formed and produces chemiluminescence in the dark.…”

Section: Resultsmentioning

confidence: 52%

Experimental and DFT Computational Insight into Nitrosamine Photochemistry—Oxygen Matters

et al. 2017

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A nitrosamine photooxidation reaction is shown to generate a peroxy intermediate by experimental physical-organic methods. The irradiation of phenyl and methyl-substituted nitrosamines in the presence of isotopically labeled 18-oxygen revealed that an O atom was trapped from a peroxy intermediate to trimethylphosphite or triphenylphosphine, or by nitrosamine itself, forming two moles of nitramine. The unstable peroxy intermediate can be trapped at low temperature in postphotolyzed solution in the dark. Chemiluminescence was also observed upon thermal decomposition of the peroxy intermediate, that is, when a postphotolysis low-temperature solution is brought up to room temperature. A DFT study provides tentative information for cyclic nitrogen peroxide species on the reaction surface.

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Section: Resultsmentioning

confidence: 52%

Experimental and DFT Computational Insight into Nitrosamine Photochemistry—Oxygen Matters

et al. 2017

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“…A self-quenching might prevent the excited species from reacting in vivo with subcellular constituents within melanosomes and avoid deleterious effects exerted by electronically excited species, as demonstrated recently (Nascimento et al, 1986;Nascimento and Cilento, 1987). If excited states were generated during melanogenesis in vivo within the melanosomes, which usually contain as much as about 60% of the melanin pigment, the pigment itself or other organellar constituents might be activated toward potentially harmful species, e.g.…”

Section: Discussionmentioning

confidence: 96%

Studies on chemiluminescence in the enzymatic and autoxidative transformation of 3,4‐dihydroxyphenylalanine into eumelanins

Villablanca

Indig

Slawinska³

et al. 1989

J. Biolumin. Chemilumin.

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The catechol oxidase-catalysed and autoxidative transformation of 3,4-dihydroxyphenylalanine (DOPA) to eumelanin have been studied by oxygen consumption, energy transfer, absorption and fluorescence spectroscopy. Formation of transient dopachrome (lambda max = 480 nm) and dopalutin (lambda ex = 423 nm, lambda em = 491 nm) have been found in the enzymatic and autoxidative reaction. In the enzymatic reaction, neither a photon emission with quantum yield phi greater than 10(-13) nor energy transfer to triplet and singlet energy acceptors (sensitizers such as anthracene derivatives, xanthene dyes and chlorophyll-a) in water and micellar solutions have been found. The autoxidative reaction is chemiluminescent (phi = 10(-9)), the emission occurring in the 400-600 nm range. The excitation energy is not transferred to sensitizers. The effect of various enzymes and traps of active oxygen species as well as the spectral distribution of chemiluminescence indicate that there is no emission from oxygen dimoles. Carbonates and active species of oxygen are shown to participate in the chemiexcitation reaction.

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“…Another substrate that has been investigated (Nascimento and Cilento, 1987) is phenylacetaldehyde (PAA) known to be oxidized to formic acid and triplet benzaldehyde by peroxidase. PAA is very suitable for studies with organellesand also cells-because of the reactive enol form at physiological pH and its capacity to penetrate through the cell membrane.…”

Section: Hrp-catalysed Metabolization Of Diethyl-stilbestrol (Des)mentioning

confidence: 99%

Generation of triplet carbonyl compounds during peroxidase catalysed reactions

Cilento

1989

J. Biolumin. Chemilumin.

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Peroxidases, acting as oxidase upon appropriate substrates, generate carbonyl compounds in the electronically excited triplet state. These excited species can transfer energy as demonstrated by the appearance of the acceptor fluorescence or induced photochemistry concomitant with the disappearance of phosphorescence. Chlorophyll, an efficient emissive acceptor, either naturally present or artificially incorporated into organelles and cells, allows the in situ detection of biologically generated excited species. With neutrophils, the myeloperoxidase promoted acetone phosphorescence can readily be detected. In other cases, e.g. triplet benzaldehyde, it is possible to observe emission from lipid peroxidation initiated by the triplet carbonyl compound.

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Generation of Electronically Excited States in Situ. Polymorphonuclear Leukocytes Treated With Phenylacetaldehyde

Cited by 22 publications

References 22 publications

Experimental and DFT Computational Insight into Nitrosamine Photochemistry—Oxygen Matters

Experimental and DFT Computational Insight into Nitrosamine Photochemistry—Oxygen Matters

Studies on chemiluminescence in the enzymatic and autoxidative transformation of 3,4‐dihydroxyphenylalanine into eumelanins

Generation of triplet carbonyl compounds during peroxidase catalysed reactions

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