Excited singlet molecular O-2 ((1)Delta g) is generated enzymatically from excited carbonyls in the dark

Excited singlet molecular O-2 ((1)Delta g) is generated enzymatically from excited carbonyls in the dark

Author Mano, Camila M. Google Scholar
Prado, Fernanda M. Google Scholar
Massari, Julio Google Scholar
Ronsein, Graziella E. Google Scholar
Martinez, Glaucia R. Google Scholar
Miyamoto, Sayuri Google Scholar
Cadet, Jean Google Scholar
Sies, Helmut Google Scholar
Medeiros, Marisa H. G. Google Scholar
Bechara, Etelvino José Henriques Autor UNIFESP Google Scholar
Di Mascio, Paolo Google Scholar
Institution Universidade de São Paulo (USP)
Univ Fed Parana
CEA Grenoble
Univ Dusseldorf
Universidade Federal de São Paulo (UNIFESP)
Abstract In mammalian tissues, ultraweak chemiluminescence arising from biomolecule oxidation has been attributed to the radiative deactivation of singlet molecular oxygen [O-2 ((1)Delta(g))] and electronically excited triplet carbonyl products involving dioxetane intermediates. Herein, we describe evidence of the generation of O-2 ((1)Delta(g)) in aqueous solution via energy transfer from excited triplet acetone. This involves thermolysis of 3,3,4,4-tetramethyl-1,2-dioxetane, a chemical source, and horseradish peroxidase-catalyzed oxidation of 2-methylpropanal, as an enzymatic source. Both sources of excited carbonyls showed characteristic light emission at 1,270 nm, directly indicative of the monomolecular decay of O-2 ((1)Delta(g)). Indirect analysis of O2 (1Dg) by electron paramagnetic resonance using the chemical trap 2,2,6,6-tetramethylpiperidine showed the formation of 2,2,6,6-tetramethylpiperidine-1-oxyl. Using [O-18]-labeled triplet, ground state molecular oxygen [O-18(2) ((3)Sigma(g) -)], chemical trapping of O-18(2) ((1)Delta(g)) with disodium salt of anthracene-9,10-diyldiethane-2,1-diyl disulfate yielding the corresponding double-[O-18]-labeled 9,10-endoperoxide, was detected through mass spectrometry. This corroborates formation of O-2 ((1)Delta(g)). Altogether, photoemission and chemical trapping studies clearly demonstrate that chemically and enzymatically nascent excited carbonyl generates O-18(2) ((1)Delta(g)) by triplet-triplet energy transfer to ground state oxygen O-2 ((1)Delta(g)), and supports the long formulated hypothesis of O-2 ((1)Delta(g)) involvement in physiological and pathophysiological events that might take place in tissues in the absence of light.
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
PRONEX/FINEP (Programa de Apoio aos Nucleos de Excelencia)
PRPUSP (Pro-Reitoria de Pesquisa da Universidade de São Paulo)
Instituto do Milenio-Redoxoma
NAP Redoxoma (PRPUSP)
Fundo Bunka de Pesquisa Banco Sumitomo Mitsui )
John Simon Guggenheim Memorial Foundation
National Foundation for Cancer Research, Bethesda, MD, USA
Grant number FAPESP: 2006/56530-4
FAPESP: 2012/12663-1
Instituto do Milenio-Redoxoma: 420011/2005-6
FAPESP: 573530/2008-4
NAP Redoxoma (PRPUSP): 2011.1.9352.1.8
FAPESP: 2013/07937-8
Date 2014-08-04
Published in Scientific Reports. London: Nature Publishing Group, v. 4, 10 p., 2014.
ISSN 2045-2322 (Sherpa/Romeo, impact factor)
Publisher Nature Publishing Group
Extent 10
Origin http://dx.doi.org/10.1038/srep05938
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000339941700004
URI http://repositorio.unifesp.br/handle/11600/38078

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