Biomaterial Database

Chemiluminescence associated with singlet oxygen reactions with amino acids, peptides and proteins. 2007

Emilio Alarcón, and Carola Henríquez, and Alexis Aspée, and Eduardo A Lissi

Facultad de Química, Departamento de Química Física, Pontificia Universidad Católica de Chile, Santiago, Chile.

Low level chemiluminescence (CL) is observed after protein oxidation mediated by singlet oxygen produced in Rose Bengal (RB) irradiation. This CL lasts for several minutes after the end of the photolysis. In this work, the mechanism of the process was assessed from the spectral characteristics of the CL and the effect of antioxidants (Trolox or ascorbate), Ebselen (a compound with peroxidase-like activity), azide (a singlet oxygen scavenger) and D2O, added prior to or after RB irradiation. It is concluded that most of the light emission is due to formation of excited states generated in the decomposition of peroxides and/or hydroperoxides accumulated during the photolysis. Experiments carried out in the presence of several amino acids (Cys, Met, His, Tyr and Trp) and di- and tripeptides suggest that peroxides (and/or hydroperoxides) of Trp residues are mainly responsible for the CL observed after singlet oxygen-mediated protein oxidation. The much weaker CL observed after the oxidation of proteins without Trp residues supports this conclusion. A comparison of the results obtained employing free Trp, Ala-Trp and Trp-Ala dipeptides, Ala-Trp-Ala tripeptide and Trp-containing proteins supports the conclusion that blocking the amino group of the Trp moiety strongly increases the efficiency of the chemiluminescent process, producing approximately 2.5x10(-8) photons per oxidized Trp group in Ala-Trp. A mechanism comprising two chemiluminescent oxidation pathways of Trp residues is proposed to explain the results.

UI	MeSH Term	Description	Entries
D008163	Luminescent Measurements	Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.	Bioluminescence Measurements,Bioluminescent Assays,Bioluminescent Measurements,Chemiluminescence Measurements,Chemiluminescent Assays,Chemiluminescent Measurements,Chemoluminescence Measurements,Luminescence Measurements,Luminescent Assays,Luminescent Techniques,Phosphorescence Measurements,Phosphorescent Assays,Phosphorescent Measurements,Assay, Bioluminescent,Assay, Chemiluminescent,Assay, Luminescent,Assay, Phosphorescent,Assays, Bioluminescent,Assays, Chemiluminescent,Assays, Luminescent,Assays, Phosphorescent,Bioluminescence Measurement,Bioluminescent Assay,Bioluminescent Measurement,Chemiluminescence Measurement,Chemiluminescent Assay,Chemiluminescent Measurement,Chemoluminescence Measurement,Luminescence Measurement,Luminescent Assay,Luminescent Measurement,Luminescent Technique,Measurement, Bioluminescence,Measurement, Bioluminescent,Measurement, Chemiluminescence,Measurement, Chemiluminescent,Measurement, Chemoluminescence,Measurement, Luminescence,Measurement, Luminescent,Measurement, Phosphorescence,Measurement, Phosphorescent,Measurements, Bioluminescence,Measurements, Bioluminescent,Measurements, Chemiluminescence,Measurements, Chemiluminescent,Measurements, Chemoluminescence,Measurements, Luminescence,Measurements, Luminescent,Measurements, Phosphorescence,Measurements, Phosphorescent,Phosphorescence Measurement,Phosphorescent Assay,Phosphorescent Measurement,Technique, Luminescent,Techniques, Luminescent
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D010545	Peroxides	A group of compounds that contain a bivalent O-O group, i.e., the oxygen atoms are univalent. They can either be inorganic or organic in nature. Such compounds release atomic (nascent) oxygen readily. Thus they are strong oxidizing agents and fire hazards when in contact with combustible materials, especially under high-temperature conditions. The chief industrial uses of peroxides are as oxidizing agents, bleaching agents, and initiators of polymerization. (From Hawley's Condensed Chemical Dictionary, 11th ed)	Peroxide
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
D000975	Antioxidants	Naturally occurring or synthetic substances that inhibit or retard oxidation reactions. They counteract the damaging effects of oxidation in animal tissues.	Anti-Oxidant,Antioxidant,Antioxidant Activity,Endogenous Antioxidant,Endogenous Antioxidants,Anti-Oxidant Effect,Anti-Oxidant Effects,Anti-Oxidants,Antioxidant Effect,Antioxidant Effects,Activity, Antioxidant,Anti Oxidant,Anti Oxidant Effect,Anti Oxidant Effects,Anti Oxidants,Antioxidant, Endogenous,Antioxidants, Endogenous
D012395	Rose Bengal	A bright bluish pink compound that has been used as a dye, biological stain, and diagnostic aid.	Rose Bengal Sodium I 125,Rose Bengal Sodium I 131,Bengal, Rose
D014364	Tryptophan	An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.	Ardeydorm,Ardeytropin,L-Tryptophan,L-Tryptophan-ratiopharm,Levotryptophan,Lyphan,Naturruhe,Optimax,PMS-Tryptophan,Trofan,Tryptacin,Tryptan,Tryptophan Metabolism Alterations,ratio-Tryptophan,L Tryptophan,L Tryptophan ratiopharm,PMS Tryptophan,ratio Tryptophan
D026082	Singlet Oxygen	An excited state of molecular oxygen generated photochemically or chemically. Singlet oxygen reacts with a variety of biological molecules such as NUCLEIC ACIDS; PROTEINS; and LIPIDS; causing oxidative damages.	Singlet Dioxygen,Dioxygen, Singlet,Oxygen, Singlet