A comparative study of ribonuclease and lysozyme oxidation and nitration by peroxynitrite and myeloperoxidase | Health & Environmental Research Online (HERO)

HERO ID

975856

Reference Type

Journal Article

Subtype

Abstract

Title

A comparative study of ribonuclease and lysozyme oxidation and nitration by peroxynitrite and myeloperoxidase

Author(s)

Vaz, SM; Prado, FA; Di Mascio, P; Augusto, O

Year

2008

Is Peer Reviewed?

Yes

Journal

Free Radical Biology and Medicine
ISSN: 0891-5849
EISSN: 1873-4596

Volume

45

Issue

Suppl.

Page Numbers

S75-S75

Language

English

Web of Science Id

WOS:000260867900212

URL

http://www.sciencedirect.com/science/article/pii/S0891584908006242
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Relationship(s)

is part of a larger document 3452652 SFRBM's 15th Annual Meeting: Program and Abstracts

Abstract

Protein oxidation and nitration are commonly employed as biomarkers of the formation of oxidative and nitro-oxidative species in cells, experimental animals and human tissues. However, there is a lack of information on the behavior of important nitro-oxidative mediators, such as peroxynitrite and myeloperoxidase towards protein targets. Here we compared the oxidative modifications promoted by 1 mM peroxynitrite and MPO/H2O2 (1 mM)/NO2 − (1 mM) on ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp) at pHs 5.4, 6.4, and 7.4. EPR and product analysis (HPLC/MS-ESI of pronase hydrolysates and HPLC-MSMaldi-ToF and MS-ESI of tryptic digests) provided the following results. (I) Total ribonuclease and lysozyme oxidation, including protein radical formation, was higher at pH 5.4 and 7.4 for MPO and peroxynitrite, respectively. (II) in the Trp-containing lysozyme the main target was Trp62/63 and Tyr23 for peroxynitrite and MPO, respectively. (III) in ribonuclease, peroxynitrite modified mainly accessible Tyr115 and Tyr92/97 whereas, MPO modified most Tyr residues suggesting protein unfolding. (IV) Both oxidants produced hydroxylated products of Trp (lysozyme-Trp62) and Tyr (ribonuclease-Tyr73) in surface-exposed residues. in conclusion, the results indicate that Trp residues are particularly important target for peroxynitrite. Also, that MPO is likely to be a more efficient promoter of protein nitro-oxidative damage at acid pH. Supported by FAPESP and CNPq.

Conference Name

Society for Free Radical Biology and Medicine15th Annual Meeting

Conference Location

Indianapolis, IN

Conference Dates

November 19-23, 2008