||Bechara, Etelvino J. H; Medeiros, Marisa H. G; Catalani, Luiz H; Soares, Carlos H. L; Monteiro, Hugo P; Abdalla, Dulcinéia S. P; Cristoff, Marcello; Hermes-Lima, Marcelo; Pereira, Benedito; Demasi, Marilene; Nantes, Iseli L; Costa, Cristine A; Rocha, Maria Eliane M; Di Mascio, Paolo; Wendel, Caio M. A; Onuki, Janice; Penatti, Carlos A. A; Pinto, Adriana P.|
||Enolizable carbonyl and imino metabolites may act as endogenous sources of reactive oxygen species|
||Ciênc. cult. (Säo Paulo);47(5/6):346-57, Sept.-Oct. 1995. ilus.
||Highly reactive oxyradicals and electronically excited triplet carbonyls can be generated in vitro by iron complexes and heme enzyme-catalyzed aerobic oxidation of synthetic or naturally occurring substances capable of enolization in aqueous medium. Monoenols and enamines, obtained by (alpha-methyne-carbonyl and -imine enolization, undergo dioxygen insertion and ultimately originate triplet species; e.g., isobutanal, 3-methylacetoacetone, Schiff bases. In turn, (alpha-hydroxy- and (alpha-aminocarbonyls (e.g., carbohydrates, 5-aminolevulinic acid) tautomerize to enediols and enolamines and yield oxyradicals, initiated by electron transfer to dioxygen, as polyphenols (e.g., 6-hydroxydopamine) and polyphenolamines do. Free radicals and excited species have been implicated in several normal and pathological processes. We here briefly review our contributions to this research area, emphasizing a possible in vivo prooxidant role for 5-aminolevulinic acid, the heme precursor accumulated in several porphyric disorders (e.g., lead poisoning, acut intermittent porphyria, tyrosinosis).|
Técnicas In Vitro
Espécies Reativas de Oxigênio
||BR1.1 - BIREME|