Hydroxyl radical oxidation of cytochrome c by aerobic radiolysis.
Free Radic Biol Med
; 37(8): 1203-13, 2004 Oct 15.
Article
en En
| MEDLINE
| ID: mdl-15451060
The reaction of radiolytically generated *OH with cytochrome c was investigated by mass spectrometry. Tryptic digestion and characterization of the oxidized peptides by MALDI-TOF and ESI tandem mass spectrometry identified eight different amino acid residues with oxidized side chains with no cleavage of the protein detected. Solvent-accessible aromatic and methionine residues are the most susceptible to oxidation by *OH. These results support the careful use of *OH in characterizing protein surfaces. Dose-response studies identified the residues most prone to oxidation to be Phe-36, Phe-46, and Met-80. Hydroxylation of Phe-36 and Phe-46 should serve as indicators of the presence of *OH in the mitochondrial intermembrane space. Using solutions containing 50 at.% (18)O, our study also provides a novel method of determining the source of oxygen during *OH-mediated oxidation of proteins and contributes to identification of the modified residue type, with Phe>Tyr>Met in (18)O incorporation. During aerobic radiolysis, UV-vis spectroscopy indicates that ferrocytochrome c reaches a steady state concomitant with reduction of the heme.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Radiólisis de Impulso
/
Radical Hidroxilo
/
Citocromos c
Límite:
Animals
Idioma:
En
Revista:
Free Radic Biol Med
Asunto de la revista:
BIOQUIMICA
/
MEDICINA
Año:
2004
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos