Specific electrochemical nitration of horse heart myoglobin.
Arch Biochem Biophys
; 392(2): 169-79, 2001 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-11488590
ABSTRACT
Earlier findings on electronitration of hen egg-white lysozyme demonstrated a product which was mononitrated at Tyr23, by ion-exchange chromatography, absorbance at 430 nm, dithionite reduction, and Edman sequencing of a nitrated proteolytic peptide. However, the whole protein was not sequenced; therefore, although the enzyme remained active upon nitration, reaction at other residues could not be completely eliminated. This study has now been extended to the redox protein myoglobin. We demonstrate the novel electronitration (electrooxidation in the presence of nitrite) of a specific tyrosine residue in horse heart myoglobin and also in apomyoglobin. Production of the yellow chromophore, 3-nitrotyrosine (3-NT), was apparent in apomyoglobin from A430 but was masked in holomyoglobin by the Soret band. In both cases, the presence of 3-NT in the electronitrated samples was further indicated by the binding of antibody to 3-NT in Western blots. High-resolution electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry revealed a reaction product at [M + 45] (consistent with substitution of NO2 for H), indicating that the nitration reaction is the only reaction occurring which gives rise to a change in mass in the electrooxidation. Fragmentation mass spectrometry identified the nitration site as Tyr103, with no nitration at Tyr146. The procedure may be useful in preparing model nitrated proteins for the study of disease mechanisms.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tirosina
/
Eletroquímica
/
Miocárdio
/
Mioglobina
/
Nitrogênio
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Reino Unido