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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Radical acylation of L-lysine derivatives and L-lysine-containing peptides by peroxynitrite-treated diacetyl and methylglyoxal

Texto completo
Tokikawa, R. [1] ; Loffredo, C. [1] ; Uemi, M. [2] ; Machini, M. T. [1] ; Bechara, E. J. H. [1, 2]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-05508 Sao Paulo - Brazil
[2] Univ Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Exatas & Terra, Diadema, SP - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: Free Radical Research; v. 48, n. 3, p. 357-370, MAR 2014.
Citações Web of Science: 3

Highly electrophilic alpha-dicarbonyls such as diacetyl, methylglyoxal, 3-deoxyglucosone, and 4,5- dioxovaleric acid have been characterized as secondary catabolites that can aggregate proteins and form DNA nucleobase adducts in several human maladies, including Alzheimer' s disease, rheumatoid arthritis, diabetes, sepsis, renal failure, and respiratory distress syndrome. In vitro, diacetyl and methylglyoxal have also been shown to rapidly add up the peroxynitrite anion ( k (2) similar to 10 (4) - 10 (5) M (- 1) s (- 1)), a potent biological nucleophile, oxidant and nitrosating agent, followed by carbon chain cleavage to carboxylic acids via acetyl radical intermediate that can modify amino acids. In this study, we used the amino acid derivatives Ac-Lys-OMe and Z-Lys-OMe and synthesized the tetrapeptides H-KALA-OH, Ac-KALA-OH, and H-K( Boc) ALA-OH to reveal the preferential Lys amino group targeted by acyl radical generated by the a - dicarbonyl/peroxynitrite system. The pH profiles of the reactions are belll-shaped, peaking at approximately 7.5; hence, they are close to the pKa values of ONOOH and of the catalytic H (2) PO4 (-) anion. RP-HPLC and ESI-MS analyses of reaction products confi rmed N-alpha-and N-epsilon-acetylation of Lys by diacetyl as well as acetylation and formylation by methylglyoxal, with preference for the a -amino group. These data suggest the possibility of radical acylation of proteins in epigenetic processes, where enzymatic acetylation of these biomolecules is a welldocumented event, recently reported to be as critical to the cell cycle as phosphorylation. Also noteworthy is the observed formylation of L-Lys containing peptides by methylglyoxal never reported to occur in amino acid residues of peptides and proteins. (AU)

Processo FAPESP: 06/56530-4 - Estresse redox e carbonílico associado a alfa-aminocetonas e beta-cetoácidos endógenos: mecanismos e biomarcadores
Beneficiário:Etelvino José Henriques Bechara
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 08/11695-1 - Tecnologias alternativas ná química dè peptídeos: solvólise mediada pôr íons metálicos, biocatálise, aquecimento convencional e microondas
Beneficiário:Maria Teresa Machini
Linha de fomento: Auxílio à Pesquisa - Regular