LC-MS/MS screening strategy for unknown adducts to N-terminal valine in hemoglobin applied to smokers and nonsmokers.
Chem Res Toxicol
; 27(12): 2062-70, 2014 Dec 15.
Article
em En
| MEDLINE
| ID: mdl-25350717
ABSTRACT
Electrophilically reactive compounds have the ability to form adducts with nucleophilic sites in DNA and proteins, constituting a risk for toxic effects. Mass spectrometric detection of adducts to N-terminal valine in hemoglobin (Hb) after detachment by modified Edman degradation procedures is one approach for in vivo monitoring of exposure to electrophilic compounds/metabolites. So far, applications have been limited to one or a few selected reactive species, such as acrylamide and its metabolite glycidamide. This article presents a novel screening strategy for unknown Hb adducts to be used as a basis for an adductomic approach. The method is based on a modified Edman procedure, FIRE, specifically developed for LC-MS/MS analysis of N-terminal valine adducts in Hb detached as fluorescein thiohydantoin (FTH) derivatives. The aim is to detect and identify a priori unknown Hb adducts in human blood samples. Screening of valine adducts was performed by stepwise scanning of precursor ions in small mass increments, monitoring four fragments common for the FTH derivative of valine with different N-substitutions in the multiple-reaction mode, covering a mass range of 135 Da (m/z 503-638). Samples from six smokers and six nonsmokers were analyzed. Control experiments were performed to compare these results with known adducts and to check for artifactual formation of adducts. In all samples of smokers and nonsmokers, seven adducts were identified, of which six have previously been studied. Nineteen unknown adducts were observed, and 14 of those exhibited fragmentation patterns similar to earlier studied FTH derivatives of adducts to valine. Identification of the unknown adducts will be the focus of future work. The presented methodology is a promising screening tool using Hb adducts to indicate exposure to potentially toxic electrophilic compounds and metabolites.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Valina
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Hemoglobinas
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Fumar
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Cromatografia Líquida
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Espectrometria de Massas em Tandem
Tipo de estudo:
Diagnostic_studies
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Observational_studies
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Risk_factors_studies
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Screening_studies
Limite:
Humans
Idioma:
En
Revista:
Chem Res Toxicol
Assunto da revista:
TOXICOLOGIA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Suécia